fix: stabilize CSS bundles across platforms

[LeemanCheung]

Summary

• use an explicit dsh-token-usage_[local] CSS Module namespace instead of Lightning CSS's platform-sensitive path hash
• keep a fixed POSIX virtual location for path-aware transforms and normalize CSS source line endings
• add regression coverage for the canonical path contract, plugin-scoped names, and exact generated class names
• rebuild the committed browser bundle from the corrected configuration

Root cause

The existing configuration normalized checkout-relative paths but still used Lightning CSS's built-in [hash]. Historical CI showed that Windows-generated committed bundles used different CSS Module prefixes from an Ubuntu rebuild. The first revision of this PR proved that even identical POSIX input strings are interpreted with host-specific path semantics inside Lightning CSS, so path normalization alone was insufficient. The final fix removes path hashing from class names and uses the plugin ID as a deterministic collision namespace.

The CI correctly retained git diff --exit-code -- lib; no quality gate was disabled. Typecheck, tests, package validation, and same-run deterministic builds were already passing before the final cross-platform check.

Verification

• npm run typecheck — passed
• npm test — 23 files, 135 tests passed
• targeted build-config regression — 4 tests passed
• two consecutive npm run build runs produced identical SHA-256 values for lib/index.js, lib/client.js, and lib/client.js.map
• npm pack --dry-run --json — 41 files validated
• git diff --check — passed

The remaining acceptance check is the pull request's Ubuntu CI rebuild matching the bundle generated on Windows.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-02T03:07:10.001344Z	9445740	PR opened

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