ui(skill): consistent result rendering across add/remove/update

[codeaholicguy]

Current output

skill add (from renderSkillInstallResult):

  -> ~/.claude/skills/frontend-design/SKILL.md (already exists, skipped)
Successfully installed: frontend-design
ℹ  Source: anthropics/skills
ℹ  Installed to (global): claude, codex

skill remove:

  -> Removed from /path/claude/skills/foo
✔ Successfully removed from 3 location(s).

Problems

1. -> result lines are unstyled and inconsistent: install uses -> target (action) with a parenthetical that sometimes contains a sentence (already exists, skipped), remove uses -> Removed from target — plain text, no color, no glyph, different phrasing for the same "per-location result" concept.
2. Successfully installed: line is plain ui.text while remove uses ui.success (✔) — the most important line of the output has no success styling in add.
3. Naive pluralization: 3 location(s), feature doc(s) (docs command).
4. Metadata lines switch to ℹ info styling (Source:, Installed to) while the equivalent lines in remove are also ui.info but labeled Note: — the key (Source/Installed to/Note) and styling conventions don't line up between the two flows.
5. ui.summary in skill update (updated/skipped/failed with error details) is the best output in the skill family — but add/remove don't follow its pattern; three render styles for three subcommands.

Expectation

• One per-item line convention across add/remove/update: ✔/⚠/✖ <target> — <action or reason> with color by outcome (installed green, skipped dim/yellow, failed red).
• Headline result through ui.success/ui.warning consistently (✔ Installed frontend-design from anthropics/skills).
• Metadata (Installed to, Source, Note: cached copy preserved) as dim lines under the headline, same order in every flow.
• Pluralization via the shared helper (3 locations).
• Long term: converge on the ui.summary shape used by skill update so all mutating skill subcommands render alike.

Files: packages/cli/src/commands/skill/skill.render.ts (renderSkillInstallResult, renderSkillRemoveResult, renderUpdateSummary)