fix(links): respect case in POSIX file links

[lnieuwenhuis]

File-link resolution lowercases every path, so two POSIX siblings that differ only by case resolve to the same target.

Only fold case for Windows filesystem paths (drive-letter or UNC roots); POSIX paths keep their case. Covers POSIX siblings, double-slash POSIX vs UNC, drive roots, UNC share roots, and encoded trailing spaces.

Ports the containment rule of #9309 into the current shared resolver in packages/client-runtime (consumed by web and mobile) instead of the stale web-local diff.

Built with muse-spark-1.3-contributor via OpenCode in T3 Code.

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Note

Medium Risk
Changes core path containment used by markdown file links and workspace-relative display across clients; behavior shifts for POSIX case mismatches but is narrowly scoped and heavily tested.

Overview
POSIX workspace containment is now case-sensitive, so paths like /tmp/.../project are no longer treated as inside /tmp/.../Project. Previously, workspace-relative resolution lowercased every path and could collapse case-distinct siblings.

The shared resolver in packages/client-runtime adds isWindowsFilesystemPath and uses it in workspaceRelativeFilePath so only Windows drive-letter roots and backslash UNC shares compare case-insensitively; POSIX paths (including // double-slash, which are not UNC) keep exact casing. formatWorkspaceRelativePath in the web app follows the same rule.

Tests cover Windows/UNC/drive-root behavior, encoded trailing spaces on file paths, and markdown link metadata that must not mark case-mismatched POSIX paths as workspace files.

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Note

Fix case sensitivity in POSIX workspace file links

Workspace containment checks were case-insensitive for all paths, causing case-distinct POSIX siblings to be wrongly treated as workspace members. The fix adds isWindowsFilesystemPath to classify drive-letter and backslash UNC paths as Windows, then applies case-insensitive comparison only for those roots and case-sensitive comparison for POSIX roots.

• workspaceRelativeFilePath in markdownLinks.ts and formatWorkspaceRelativePath in filePathDisplay.ts both select case sensitivity from the workspace root via the new classifier.
• Double-slash forward-slash paths are not treated as UNC paths, so they stay POSIX and case-sensitive.
• Risk: POSIX workspace roots that previously matched case-variant paths now reject them; any consumer relying on the old case-insensitive POSIX behavior will see those paths fall outside the workspace.

^{Macroscope summarized ca0e9c5.}

[macroscopeapp]

Approvability

Verdict: Approved at ca0e9c5

Macroscope's review found this PR approvable — This is a narrowly scoped bug fix that makes POSIX workspace-link containment case-sensitive while preserving Windows behavior. Production changes are limited to existing link metadata and path display logic, with focused cross-platform tests and no defaults, schema, deployment, security, or static-analysis changes.

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[juliusmarminge]

Superseded by merged #9309 (same POSIX case-sensitive file-link containment fix).