feat: raw fetch - a sanctioned intake for a URL into incoming/, HTML as received plus derived text (#120)

Files changed:
- 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/raw_cmd.py
- tools/chemenu/tests/test_cli.py
- tools/chemenu/tests/test_portability.py
- tools/chemenu/tests/test_raw_fetch.py
- tools/chemenu/web_capture.py

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

tools/README.md

@@ -105,6 +105,7 @@ tools/
     version.py             the stack version: VERSION, the release stamp, the compatibility rule
     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
     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