fix(web): preserve POSIX path casing in file links

[AksharP5]

What Changed

Markdown file links now use the shared project-path comparison policy for workspace containment. POSIX paths remain case-sensitive, while Windows drive and UNC paths remain case-insensitive.

The same containment result now drives both tooltip formatting and click routing.

Why

On POSIX, link containment lowercased both paths. A link to a case-distinct sibling such as project/probe.txt could therefore be treated as Project/probe.txt inside the workspace and open the wrong file in the right-panel preview.

Fixes #4804

UI Changes

Before — outside sibling misclassified

After — outside sibling remains absolute

After — inside-workspace display remains relative

t3PR.mp4

Verification

• vp test run packages/shared/src/path.test.ts apps/web/src/markdown-links.test.ts apps/web/src/filePathDisplay.test.ts — 54 tests passed
• Targeted lint passed for the changed files
• vp run --filter @t3tools/shared typecheck passed
• vp run --filter @t3tools/web typecheck passed

Checklist

• This PR is small and focused
• I explained what changed and why
• I included before/after screenshots for the UI behavior
• I included a video for the interaction change

Model: GPT-5.6 Sol | Harness: Codex in T3 Code

Note

Fix POSIX path casing preservation in file links for workspace-relative display

• Adds resolveWorkspaceRelativePath to filePathDisplay.ts to compute workspace-relative paths with correct case sensitivity: exact-match for POSIX, case-insensitive for Windows and UNC paths.
• Refactors formatWorkspaceRelativePath to preserve drive roots (e.g. C:/) and filesystem roots (/) in display output instead of collapsing them.
• Extracts normalizePathCaseForComparison into packages/shared/src/path.ts as a reusable utility; Windows/UNC paths are lowercased and backslash-normalized, POSIX paths are returned unchanged.
• Updates markdown-links.ts to use resolveWorkspaceRelativePath for workspaceRelativePath in link metadata, replacing a local helper that unconditionally lowercased paths.
• Behavioral Change: POSIX file links are now case-sensitive — previously, paths were always lowercased for comparison, which could cause mismatches on case-sensitive filesystems.

^{Macroscope summarized 2a250cb.}

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Note

Medium Risk
Changes core path comparison used for link preview routing and display; behavior shifts on case-sensitive filesystems but is covered by expanded tests.

Overview
Fixes workspace containment for markdown file links and tooltips so POSIX paths stay case-sensitive, while Windows drive and UNC paths stay case-insensitive.

Adds shared resolveWorkspaceRelativePath (used by display formatting and link metadata) and normalizePathCaseForComparison in @t3tools/shared/path, replacing logic that always lowercased paths for comparison. Display formatting now keeps drive and filesystem roots (e.g. C:/, /) and handles UNC share roots correctly.

A link to a case-distinct sibling (e.g. project/ vs workspace Project/) is no longer treated as in-workspace, so preview routing and relative labels match the real path.

^{Reviewed by Cursor Bugbot for commit dce9bff. Bugbot is set up for automated code reviews on this repo. Configure here.}

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[cursor]

Cursor Bugbot has reviewed your changes using high effort and found 1 potential issue.

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[macroscopeapp]

Approvability

Verdict: Needs human review

This bug fix changes path comparison behavior from unconditional case-insensitivity to platform-aware handling (POSIX case-sensitive, Windows case-insensitive). While well-tested, changes to core path resolution logic that affect runtime behavior warrant human review.

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[t3dotgg]

Note

🤖 GPT-6 Astra (preview) responding on behalf of Theo

This was closed as part of an automated cleanup pass. If you believe it was closed in error, reply here and we will get it reopened.

Closing in favor of the smaller case-policy change in #9309, where review continues. Both address POSIX file-link containment. The filesystem-root and encoded trailing-space cases are recorded there for the shared resolver update, without taking this PR's broader path rewrite or treating every double-slash path as Windows UNC.