[mixxer]

Fixes #3086

Pending-change detection now includes current source discovered by the existing include helper and previously indexed included paths, so Git-ignored first-party source reports additions, modifications and deletions. Existing scope checks and content hashing still decide the result. There is no size/mtime shortcut in this check.

Extracted from downstream PR15, commits aff678c496251fbb2eee0efc7069501b7e343db8 and 195734e03b5f6d0f23b278d69bf7b3b69cf38055, without the vendor-directory policy or Android tools. The source change is seven lines and uses existing helpers.

This changes pending status only. The existing sync metadata prefilter is unchanged; an edit preserving both size and mtime can still require a forced re-index to refresh the graph.

Validation

• macOS arm64, Node 24.21.0, fresh npm ci --ignore-scripts using the pinned lockfile; npm run build passed.
• Full portable suite: 810 files passed, 18 skipped; 9,231 tests passed, 422 skipped, zero failures (npm test -- --minWorkers=1 --maxWorkers=4, CODEGRAPH_KERNEL=0).
• New regression covers clean status, excluded noise, a same-size edit with restored mtime, an ignored addition and a deletion. It fails on the unmodified upstream control and passes here, on portable and native extraction paths.
• Bounded cost sample under concurrent suite load, 1,000 explicitly included Java files / 1,062,890 bytes, median of seven warm calls: about 59 ms before and 142 ms after. The added work discovers and hashes included source; there is no new cache or metadata shortcut. This is not a release performance guarantee.
• Fresh checkout of the exact published head ee949262995fcbff01128d87b4cdb69b2beb6ce1: automatic build passed; included-source status, Git-ignore parity, Git subdirectory status and the new upstream Python-supertype regression suite all passed (15 tests / 4 files).
• Existing Git-ignore parity cases pass with the pinned ignore 7.0.14. git diff --check passed. Published source/test/changelog blob SHAs match the locally validated files.

Based on current upstream cd04b21a314757b867de36ba5992ffc32eb3cb1c. The full suite ran on the same source before its independent Python-supertype change; the status code is unchanged by that upstream commit. The new upstream changelog entry is preserved. No Node 22, Linux or Windows run is claimed. Draft for maintainer review.