feat: raw capture / raw status / --replaces-bundle - documentation from git repositories as a bundle, with drift reporting (#177)

New repo_capture module: resolve a branch or tag-pattern ref rule, fetch it
shallowly by name into a bare cache, read the glob-selected files as blobs,
and record repo/ref/commit/globs/capture fields in _capture.json. raw status
reports changed captured bundles as A/M/D; raw accept --replaces-bundle swaps
a captured bundle for its new edition at the same address. iter_raw_files now
skips _capture.json and anchors the CONTRACT.md exclusion to raw/CONTRACT.md.

Files changed:
- .gitignore
- CHANGES.md
- README.md
- VERSION
- instructions/wiki-ingest/SKILL.md
- raw/CONTRACT.md
- tools/CONTRACT.md
- tools/README.md
- tools/chemenu/cli_contract.py
- tools/chemenu/commands/dist_cmd.py
- tools/chemenu/commands/docs_verify.py
- tools/chemenu/commands/raw_cmd.py
- tools/chemenu/config.py
- tools/chemenu/repo_capture.py
- tools/chemenu/tests/test_cli.py
- tools/chemenu/tests/test_raw_capture.py

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SnAJ7Z3CpVD3PRbN73QtU2

tools/README.md

@@ -106,6 +106,7 @@ tools/
     kb_state.py            the KB version (.wikitool-kb.json) and the migration chain
     corpus_diff.py         invariant comparison of kb/ between two revisions
     web_capture.py         `raw fetch`'s core: fetch a page, decide its charset, derive Markdown-like text from the HTML - standard library only, deterministic
+    repo_capture.py        `raw capture`/`raw status`'s core: resolve a ref rule, fetch it into a bare cache, select files by glob as blobs, the `_capture.json` manifest - git with the host's credentials, never a prompt
     search/                pluggable search backends, plus service.py - the search core
     tasks/                 the task-tracker provider layer: protocol.py (TaskReader/TaskWriter), config.py (.wikitool-tasks.json), one module per adapter - no instruction ever learns which provider it is
     commands/              one module per command or command group: the terminal adapters