Checkpoint web parity through Chromium input tasks

docs/status/M12-04B.md

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+# M12-04B Status
+
+status: done
+task: normalize POSIX/Windows separators, dot segments, percent encoding, and Unicode names
+updated: 2026-08-17 America/New_York
+enablingTask: false
+parityStateChange: false
+
+## Scope
+
+The shared project-asset path normalizer now emits one canonical `/`-separated path. It accepts
+equivalent POSIX/Windows separators, removes `.` segments, resolves bounded `..` segments without
+allowing project-root escape, decodes percent-encoded UTF-8 once, and applies Unicode NFC normalization.
+Residual percent octets, malformed encoding, controls, absolute paths, URI schemes, and traversal beyond
+the project remain fail-closed.
+
+## Evidence
+
+- `npm --prefix web run test:library-path-normalization` passed 4/4 unit tests.
+- Separator and dot aliases converge to one idempotent canonical path.
+- Percent-encoded separators/dot segments and decomposed Unicode names match the canonical project asset
+  locator used by the M12-04A source admission path.
+- Re-decoding, malformed percent encoding, and project-root escape return stable path errors.
+- `npm --prefix web run typecheck` passed after closing the prior library wrapper/parser type errors.
+
+## Artifact Hashes
+
+- parent manifest: `af80827d925ddd96d8541e446e0f70c956fd4c56e64ac984d187f5449df4cb0d`
+- normalizer: `6109d05251fc7355ac32d4c0d8298f85ea8b731767c76c394577c4e44652a6bf`
+- source admission: `67a1808f225194a09a72987c5340c7494c5fa8d99dffde40664a11a779caedeb`
+- unit: `abde64c60397541e92a83dd9e4a24e65faf340a8d046650604c101a21037c777`
+- manifest: `8cd29c3f5281082584fc6aefe2ec385a2eedf8116e837a4db54c391391ff8f98`
+- package commands: `cfb232baa494ff59f6c8d65514a08c86332ee9354350b2a0392b6f932a7ee42c`
+
+## Next Task
+
+`M12-04C`: reject absolute paths, UNC, drive paths, NUL, control characters, and origin escape.
+
+## Rollback
+
+Remove the path normalizer changes, unit suite, manifest, package command, and this status entry. Restore
+M12-04A to pending and move the machine queue back to `M12-04B`. No parity ledger rollback is required.