feat(tui): pi-style dock, Shift-Tab effort cycle, MCP loading line, pi-tui v1.0.1 (#369)

## Requirement or Bug

Give the TUI pi's fixed-bottom dock, make Shift-Tab cycle thinking
effort, replace per-server MCP lines with one loading line, and sync
pi-tui to upstream v1.0.1.

## Bug Reproduction Steps

N/A (feature PR). The Shift-Tab part fixes a mismatch: the welcome tip
said "shift+tab cycles thinking effort", but Shift-Tab toggled plan
mode.

## Root Cause

N/A for the dock, effort cycle, and pi-tui sync. For the MCP line: each
server that connected printed its own permanent `MCP server "x"
connected · N tools` line. While fixing that, the startup status
snapshot could also overwrite newer live `mcp.status` events, which
could leave a stale "loading" state on screen. Live events now win over
the snapshot.

## Code Changes

Seven commits, each one slice:

1. **Fullscreen by default** (`tui/config.ts`, `tui-mode-selector.ts`):
`DEFAULT_TUI_CONFIG.tuiMode` is `fullscreen`, and the "(experimental)"
label is gone. On exit, fullscreen still replays the transcript to the
main screen.
2. **Shift-Tab cycles effort** (`editor-keyboard.ts`,
`pythinker-tui.ts`, `commands/config.ts`): Shift-Tab steps through the
model's effort segments (without `off`) and wraps. Boolean-thinking
models toggle on/off. It uses `performModelSwitch` with a new `quiet`
option, so a key press adds no transcript line. The pick lasts for this
session only (`/effort` still saves it). While a reply streams, the key
does nothing. When no prompt highlight is active, the prompt frame uses
the theme's `effort*` color; plan, bash, and slash highlights still take
precedence. The tip, help panel, and docs are updated.
3. **Plain rules** (`custom-editor.ts`): the prompt is drawn as two `─`
rules with no sides. When a `/btw` panel is attached above
(`connectedAbove`), the old box is kept, so the panel border still
closes.
4. **Spinner in the top rule** (`activity-pane.ts`,
`activity-spinner.ts`, `custom-editor.ts`): while the agent works, the
editor's top rule becomes `── ⠋ Working · tip ───`. The spinner keeps
its lifecycle; only where it draws changes, so the dock height does not
change.
5. **MCP loading line** (`session-event-handler.ts`, new
`mcp-loading-line.ts`): one `● Loading MCP: a, b` line with the shared
blinking `STATUS_BULLET`. It lists only the servers still pending and is
removed when none are left. Failed and needs-OAuth servers still print
their own line, which stays.
6. **pi-tui upstream v1.0.1** (`packages/pi-tui`): a three-way merge
from the old sync point `53816d7` (v0.85.1) to `a7229ddc`. Fork changes
are kept. Upstream's private `asciiVisibleWidth` is renamed
`asciiTabVisibleWidth`, because the fork already exports a function with
that name. Upstream's new files received only `!`/bracket fixes for our
stricter tsconfig. The darwin `.node` prebuilds were rebuilt from the
reviewed `darwin-platform.m`. Their exports and linked libraries match
upstream's v1.0.1 binaries. `UPSTREAM.md` records the new sync point. No
new dependencies.
7. Changesets.

## Behavior Changes and Affected Users

| Behavior | Before | After | Who relies on the old behavior | Escape
hatch |
|---|---|---|---|---|
| Default TUI mode | `regular` (native scrollback) | `fullscreen` (fixed
bottom dock, alt screen) | New installs and users with no `tui.toml`.
Existing `tui.toml` files already contain `tui_mode = "regular"` and are
not affected. | `tui_mode = "regular"`, `/settings` → TUI mode |
| Shift-Tab | toggles plan mode | cycles thinking effort | TUI users who
toggle plan mode with the key | `/plan` |
| Shift-Tab while streaming | toggled plan mode | does nothing | same as
above | `/plan` |
| Prompt frame color | plan/bash/slash highlight, otherwise neutral |
when not highlighted, the effort color | none | none (visual only) |
| Prompt editor frame | rounded box | two plain rules (box kept while
`/btw` is attached) | none | `tui_mode = "regular"` keeps the regular
layout, but the frame is plain in both modes |
| Working spinner | own row above the prompt | inside the prompt's top
rule | none | none |
| MCP startup output | one permanent line per connected server | one
temporary blinking line; failed and needs-auth lines are unchanged |
users who read tool counts from the chat | the welcome card still shows
`MCP N connected`; `/mcp` lists servers |
| Status snapshot vs live MCP events | snapshot could overwrite newer
events | live events win | none | none |
| pi-tui internals | v0.85.1 | v1.0.1 (WezTerm image scroll, Kitty
non-PNG convert, ANSI order fix) | none | none |

Affected modules: `apps/pythinker-code/src/tui/**`, `packages/pi-tui`,
docs (`configuration/config-files.md`, `guides/interaction.md`,
`reference/keyboard.md`). Print mode, web, desktop, ACP, and SDK are not
touched. Tests: TUI config tests (default and pinned `regular`), the
editor-keyboard Shift-Tab cycle, editor side-border and plain-rule
tests, activity-pane rule placement, MCP loading-line
appear/shrink/clear, and the pi-tui `node --test` suite (1101 pass).

Checked manually with tmux at 150x45 and 80x24, in fullscreen and
regular mode. Shift-Tab changed `max → low → high` on DeepSeek V4.1
Flash. A slow stdio MCP fixture showed the blinking line shrink and then
clear.

## Checklist

- [x] I have read the
[CONTRIBUTING](https://github.com/PyModel/pythinker-code/blob/main/CONTRIBUTING.md)
document.
- [ ] I have linked a related issue (external PRs: issue must have a
maintainer's `/approve`).
- [x] I have added tests that prove my feature works.
- [x] The behavior-change table above is complete, and every removed
behavior or flipped default is named in the changeset and either has an
escape hatch or was explicitly approved by a maintainer in this PR.
- [x] Ran `gen-changesets` skill, or this PR needs no changeset.
- [x] Ran `gen-docs` skill, or this PR needs no doc update.


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **New Features**
* The TUI now defaults to fullscreen, with the prompt fixed at the
bottom and in-app scrolling. Choose Regular mode to keep chat in
terminal scrollback; saved mode settings are preserved.
* Shift-Tab cycles through the current model’s thinking efforts. Use
`/plan` to toggle Plan mode.
* Connecting MCP servers appear together in a temporary loading line;
failures and servers needing authentication remain individually visible.
* Added support for clipboard file paths, improved image display in
supported terminals, and more responsive wheel scrolling.
* **Improvements**
* Autocomplete better handles paths, punctuation, and CJK text. LaTeX
rendering supports more script and cases layouts.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: elkaix

.changeset/periwinkle-primary.md

@@ -0,0 +1,5 @@
+---
+"@pymodel/pythinker-code": patch
+---
+
+The TUI's main color (links, inline code, selections, focus, plan and shell mode) is now periwinkle instead of cyan in both the dark and light themes.

.changeset/pi-style-dock.md

@@ -0,0 +1,5 @@
+---
+"@pymodel/pythinker-code": minor
+---
+
+The TUI now opens in fullscreen by default with the prompt fixed at the bottom, drawn as two plain rules with the working spinner inside the top rule; set `tui_mode = "regular"` in `tui.toml` to keep the chat in native terminal scrollback (existing `tui.toml` files keep their saved mode).

.changeset/pi-tui-upstream-v1-0-1.md

@@ -0,0 +1,5 @@
+---
+"@pymodel/pythinker-code": patch
+---
+
+Update the terminal UI library to upstream pi v1.0.1, which keeps WezTerm images while scrolling, converts non-PNG images for Kitty, and fixes ANSI color order when a styled line is cut.

.changeset/quiet-mcp-loading-line.md

@@ -0,0 +1,5 @@
+---
+"@pymodel/pythinker-code": patch
+---
+
+The TUI now shows one "Loading MCP: …" line with a blinking dot and the names of the servers still connecting, and removes it once all have loaded, instead of one line per connected server; failures and servers that need OAuth still get their own line.

.changeset/shift-tab-effort.md

@@ -0,0 +1,5 @@
+---
+"@pymodel/pythinker-code": minor
+---
+
+Shift-Tab now cycles the current model's thinking effort (for example low, medium, high, xhigh, max) and the prompt frame takes that effort's color; Shift-Tab no longer toggles plan mode, so use `/plan` instead.

apps/pythinker-code/src/tui/commands/config.ts

@@ -401,11 +401,31 @@ export function showModelPicker(host: SlashCommandHost, selectedValue: string =
   );
 }
 
+/**
+ * Shift+Tab: step to the next thinking effort of the current model and wrap.
+ * `off` is skipped when the model declares concrete efforts. The switch is
+ * session-only and quiet, so repeated presses do not fill the transcript.
+ */
+export async function cycleThinkingEffort(host: SlashCommandHost): Promise<void> {
+  const alias = host.state.appState.model;
+  const model = host.state.appState.availableModels[alias];
+  if (model === undefined) return;
+  if (host.state.appState.streamingPhase !== 'idle') return;
+  const segments = segmentsFor(effectiveModelForHost(host, model));
+  const hasEfforts = segments.some((effort) => effort !== 'off' && effort !== 'on');
+  const cycle = hasEfforts ? segments.filter((effort) => effort !== 'off') : segments;
+  if (cycle.length < 2) return;
+  const index = cycle.indexOf(host.state.appState.thinkingEffort);
+  const next = cycle[(index + 1) % cycle.length]!;
+  await performModelSwitch(host, alias, next, false, true);
+}
+
 async function performModelSwitch(
   host: SlashCommandHost,
   alias: string,
   effort: ThinkingEffort,
   persist: boolean,
+  quiet = false,
 ): Promise<void> {
   let session = host.session;
   if (session === undefined) {
@@ -488,6 +508,7 @@ async function performModelSwitch(
     }
   }
 
+  if (quiet) return;
   let status: string;
   if (effectiveModelChanged) {
     status = persist

apps/pythinker-code/src/tui/components/chrome/activity-spinner.ts

@@ -99,6 +99,10 @@ export class ActivitySpinner extends Text {
     return this.inlineText;
   }
 
+  renderLine(): string {
+    return this.displayText;
+  }
+
   private updateDisplay(): void {
     if (this.useVerbLabels) this.label = formatThinkingSpinnerLabel();
     const frame = this.frames[this.currentFrame]!;

apps/pythinker-code/src/tui/components/dialogs/help-panel.ts

@@ -31,7 +31,7 @@ export interface HelpPanelCommand {
 
 /** Static list — keep in sync with the global editor bindings. */
 export const DEFAULT_KEYBOARD_SHORTCUTS: readonly KeyboardShortcut[] = [
-  { keys: 'Shift-Tab', description: 'Toggle plan mode' },
+  { keys: 'Shift-Tab', description: 'Cycle thinking effort' },
   { keys: 'Ctrl-G', description: 'Edit in external editor ($VISUAL / $EDITOR)' },
   { keys: 'Ctrl-O', description: 'Toggle tool output / compaction summary expansion' },
   { keys: 'Ctrl-T', description: 'Expand / collapse the todo list (when truncated)' },

apps/pythinker-code/src/tui/components/dialogs/tui-mode-selector.ts

@@ -2,16 +2,16 @@ import type { TuiMode } from '../../config';
 import { ChoicePickerComponent, type ChoiceOption } from './choice-picker';
 
 const TUI_MODE_OPTIONS: readonly ChoiceOption[] = [
+  {
+    value: 'fullscreen',
+    label: 'Fullscreen',
+    description: 'Prompt fixed at the bottom; in-app scrolling, selection, and transcript search.',
+  },
   {
     value: 'regular',
     label: 'Regular',
     description: 'Render into the terminal\'s native scrollback.',
   },
-  {
-    value: 'fullscreen',
-    label: 'Fullscreen (experimental)',
-    description: 'Alternate screen with in-app scrolling, selection, and transcript search.',
-  },
 ];
 
 export interface TuiModeSelectorOptions {

apps/pythinker-code/src/tui/components/editor/custom-editor.ts

@@ -8,11 +8,13 @@ import {
   matchesKey,
   Key,
   SelectList,
+  truncateToWidth,
   visibleWidth,
   type SelectItem,
   type TUI,
 } from '@pymodel/pi-tui';
 
+import type { ActivitySpinner } from '#/tui/components/chrome/activity-spinner';
 import { currentTheme } from '#/tui/theme';
 import { createEditorTheme } from '#/tui/theme/pi-tui-theme';
 import { printableChar } from '#/tui/utils/printable-key';
@@ -154,6 +156,8 @@ export class CustomEditor extends Editor {
   public inputMode: 'prompt' | 'bash' = 'prompt';
   public onInputModeChange?: (mode: 'prompt' | 'bash') => void;
   public connectedAbove = false;
+  /** Activity spinner drawn inside the top rule while the agent works (pi style). */
+  public ruleStatus: ActivitySpinner | undefined;
   public borderHighlighted = false;
   /**
    * Called when the user triggers "paste image" (Ctrl-V on Unix,
@@ -341,10 +345,16 @@ export class CustomEditor extends Editor {
     // overwrite it (e.g. plan-mode / slash-context highlight via
     // `editor.borderColor = chalk.hex(primary)`), so we route corners and
     // side bars through the same hook to stay in sync.
-    return wrapWithSideBorders(lines, (s) => this.borderColor(s), {
+    const wrapped = wrapWithSideBorders(lines, (s) => this.borderColor(s), {
       connectedAbove: this.connectedAbove && !this.borderHighlighted,
       label: isBash ? ` ${currentTheme.boldFg('shellMode', '! shell mode')} ` : undefined,
+      plain: !this.connectedAbove,
     });
+    const top = wrapped[0];
+    if (this.ruleStatus !== undefined && !isBash && !this.connectedAbove && top !== undefined && /^─+$/.test(stripSgr(top))) {
+      wrapped[0] = ruleWithStatus(this.ruleStatus, width, (s) => this.borderColor(s));
+    }
+    return wrapped;
   }
 
   private computeArgumentHint(): string | undefined {
@@ -842,6 +852,16 @@ export function injectPromptSymbol(
   return '  ' + rendered + ' ' + line.slice(4);
 }
 
+function ruleWithStatus(
+  status: ActivitySpinner,
+  width: number,
+  paint: (s: string) => string,
+): string {
+  status.setAvailableWidth(Math.max(1, width - 4));
+  const text = truncateToWidth(status.renderLine(), Math.max(1, width - 4), '');
+  return paint('── ') + text + ' ' + paint('─'.repeat(Math.max(0, width - 4 - visibleWidth(text))));
+}
+
 /**
  * Post-process pi-tui's editor output to draw a full box around it.
  *
@@ -854,22 +874,29 @@ export function injectPromptSymbol(
  * only if they're literal spaces — that protects the cursor-overflow
  * case where the rightmost column is an SGR-tagged inverse cursor.
  *
+ * With `options.plain`, rule rows keep plain `─` ends and content rows get
+ * no side bars: the prompt reads as two horizontal rules, like pi.
+ *
  * When `options.label` is set, it is overlaid on the left of the top border
  * (e.g. the `! shell mode` badge), replacing the leading dashes. It is only
  * applied to a plain dash run, never to a `↑/↓ N more` scroll indicator.
  */
 export function wrapWithSideBorders(
   lines: string[],
   paint: (s: string) => string,
-  options: { readonly connectedAbove?: boolean; readonly label?: string } = {},
+  options: {
+    readonly connectedAbove?: boolean;
+    readonly label?: string;
+    readonly plain?: boolean;
+  } = {},
 ): string[] {
   let seenTop = false;
   return lines.map((line) => {
     const plain = stripSgr(line);
     if (plain.length > 0 && plain[0] === '─') {
       const isTop = !seenTop;
-      const leftCorner = seenTop ? '╰' : options.connectedAbove === true ? '├' : '╭';
-      const rightCorner = seenTop ? '╯' : options.connectedAbove === true ? '┤' : '╮';
+      const leftCorner = options.plain === true ? '─' : seenTop ? '╰' : options.connectedAbove === true ? '├' : '╭';
+      const rightCorner = options.plain === true ? '─' : seenTop ? '╯' : options.connectedAbove === true ? '┤' : '╮';
       seenTop = true;
       if (plain.length === 1) return paint(leftCorner);
       const middle = plain.slice(1, -1);
@@ -886,7 +913,7 @@ export function wrapWithSideBorders(
       }
       return paint(leftCorner + middle + rightCorner);
     }
-    if (line.length === 0) return line;
+    if (line.length === 0 || options.plain === true) return line;
     const firstCh = line[0];
     const lastCh = line.at(-1);
     const head = firstCh === ' ' ? paint('│') : (firstCh ?? '');