export: export run writes selected kb/ pages as a derived, read-only version into configured target folders (markdown and command handlers, manifest, after_publish), raw accept also refuses manifest-listed files, doctor checks the section (#214); 10.0.0-beta.13

Files changed:
- CHANGES.md
- VERSION
- docs/how-to/README.md
- docs/how-to/back-up-to-a-synced-folder.md
- docs/how-to/collect-from-a-synced-folder.md
- docs/how-to/export-guidelines.md
- docs/how-to/export-to-a-synced-folder.md
- docs/reference/commands/README.md
- docs/reference/commands/exports.md
- docs/reference/commands/git.md
- docs/reference/commands/guideline-export.md
- docs/reference/commands/instance-health.md
- docs/reference/commands/raw-material-and-uploads.md
- docs/reference/configuration.md
- docs/reference/exit-codes.md
- instructions/setup-instance.md
- raw/CONTRACT.md
- tools/CONTRACT.md
- tools/README.md
- tools/chemenu/backup.py
- tools/chemenu/cli_contract.py
- tools/chemenu/commands/doctor.py
- tools/chemenu/commands/export_cmd.py
- tools/chemenu/commands/git_publish.py
- tools/chemenu/commands/raw/_common.py
- tools/chemenu/commands/raw/accept.py
- tools/chemenu/commands/raw/capture.py
- tools/chemenu/config_shapes.py
- tools/chemenu/guideline_export.py
- tools/chemenu/page_export.py
- tools/chemenu/reference_doc.py
- tools/chemenu/repo_capture.py
- tools/chemenu/tests/test_config_shapes.py
- tools/chemenu/tests/test_export_run.py

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

raw/CONTRACT.md

@@ -95,12 +95,16 @@ That is what keeps the clean-up safe: only directories the moves emptied are rem
 can go with them. A file *inside* a subdirectory is never accepted on its own; the refusal names
 both ways out - the whole folder, or the file moved up into `incoming/`.
 
-**A guideline export never comes back in.** A file whose first line (after an optional BOM)
-starts with `<!-- wikitool:export` is this stack's own output - `export guidelines` renders the
-wiki's guideline pages into it for other repositories - and `raw accept` refuses it, given on its
-own, inside a folder, or as `--replaces`/`--replaces-bundle` material, naming each one. Taken in,
-it would turn the wiki's knowledge on its way out into a source the wiki then cites for the same
-claims. `raw capture` leaves such a file out of a repository for the same reason
+**An export never comes back in.** A file that carries the stack's export marker is this stack's
+own output and `raw accept` refuses it, given on its own, inside a folder, or as
+`--replaces`/`--replaces-bundle` material, naming each one. The marker is either a first line
+(after an optional BOM) that starts with `<!-- wikitool:export` - the generated `GUIDELINES.md` of
+`export guidelines` - or, in a leading frontmatter block, a `wikitool_export:` key - a page
+`export run` wrote. A converter of an `export` target may drop the marker, so `raw accept` also
+refuses a file whose sha256 is listed in the manifest of a configured target; a missing manifest
+or a broken `export` section is a `WARN` and the check is skipped. Taken in, an export would turn
+the wiki's knowledge on its way out into a source the wiki then cites for the same claims.
+`raw capture` leaves a file with the marker out of a repository for the same reason
 ([below](#getting-a-repository-in-raw-capture)).
 
 A subdirectory used to be tolerated and ignored, for the old `incoming/<type>/` habit. It carries
@@ -447,8 +451,9 @@ is captured from a repository or accepted from `incoming/` anywhere but at the t
 folder.
 
 **Some files are never captured, by mechanism, each named in the output:** a file whose first line
-starts with `<!-- wikitool:export` (this stack's own guideline export - the wiki's knowledge on its
-way out, which must not come back in as a source), a symlink, a submodule, a file over 25 MiB, a
+starts with `<!-- wikitool:export` or opens a frontmatter block that holds a `wikitool_export:` key
+(this stack's own export - the wiki's knowledge on its way out, which must not come back in as a
+source), a symlink, a submodule, a file over 25 MiB, a
 path with a segment starting with `.` (`raw accept` refuses hidden entries anyway), a file named
 `_capture.json`, and a Git LFS pointer, which holds a reference to the content rather than the
 content.