feat: export guidelines - the guideline pages as a generated GUIDELINES.md, pushed into the captured repositories behind the Guideline Push Gate (#179)

Files changed:
- AGENTS.md
- CHANGES.md
- README.md
- VERSION
- docs/why-gates-are-code.md
- instructions/gates.md
- instructions/kb-profiles.md
- kb/CONTRACT.md
- kb/CONVENTIONS.md
- kb/CONVENTIONS.md.template
- raw/CONTRACT.md
- tools/CONTRACT.md
- tools/README.md
- tools/chemenu/cli.py
- tools/chemenu/cli_contract.py
- tools/chemenu/commands/export_cmd.py
- tools/chemenu/commands/page_ops.py
- tools/chemenu/commands/raw_cmd.py
- tools/chemenu/commands/search.py
- tools/chemenu/guideline_export.py
- tools/chemenu/kb_scan.py
- tools/chemenu/repo_capture.py
- tools/chemenu/search/filters.py
- tools/chemenu/tests/test_cli.py
- tools/chemenu/tests/test_export_guidelines.py

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

tools/README.md

@@ -106,7 +106,8 @@ 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
+    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; plus the one write back, a single-file commit pushed without force for `export guidelines`
+    guideline_export.py    `export guidelines`' core: select pages by `search` predicates, render them into one deterministic GUIDELINES.md, and recognise an export again (`EXPORT_MARKER`) - with no CLI attached
     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
@@ -132,7 +133,7 @@ interpreter the way the preflight does - `python3`, `python` on `PATH`; on Windo
 and says why.
 
 **Two consumers, one core.** The CLI is not the only caller any more. The cores
-(`search/service.py`, `lint_core.py`, `types_core.py`, `catalog.py`) hold what
+(`search/service.py`, `lint_core.py`, `types_core.py`, `catalog.py`, `guideline_export.py`) hold what
 decides an answer and import no `typer` and no `rich`; the modules under `commands/` turn
 those values into terminal output and those exceptions into exit codes.
 `api.Corpus` is the in-process entry point over the same functions - it takes a
@@ -201,8 +202,8 @@ not from a list of its own. Only read-only retrieval earns it.
 frontmatter, index statistics, cross-reference bookkeeping, log formatting,
 version arithmetic - is computed here so it comes out the same every time.
 
-**Gates are code, not prompts.** The Mass-Update Gate (`git_publish.py`) and the
-Iteration Budget Gate (`run_budget.py`) refuse in-process, because a
+**Gates are code, not prompts.** The Mass-Update Gate (`git_publish.py`), the Guideline Push
+Gate (`export_cmd.py`) and the Iteration Budget Gate (`run_budget.py`) refuse in-process, because a
 prompt-level limit is one an agent can talk itself past. Exemption lists are
 constants, never flags.