fix(skill-audit): make check 9 reachable, wrap-safe and never silently skipped

Check 9 shipped in #130 to close #118, but three defects meant it could not do the job it was
added for.

Why:
- It is INFO-only, so it always exits 0 — and SKILL.md graded exit 0 "a genuine pass" and said the
  script "prints nothing on success". Every check-9 INFO was discarded before it reached a report,
  behind three further doors that only opened on a non-zero exit.
- `parse_field_raw()` matched `(.+)`, which does not span newlines, so only the first physical line
  of a wrapped value was compared. Rewriting only the continuation line of a wrapped Description
  from a hedge to a confident claim produced no finding at all — verbatim the regression #118 was
  filed about. The bullet branch had the same shape: a wrapped bullet broke the loop and dropped
  every later entry.
- A `git show` failure at the base ref was treated as "creation, nothing to flag" and skipped the
  whole skill with no output, collapsing "absent at that ref" with "not tracked under that name".
  A gitignored `.claude/skills/` copy reported clean while the authoring path reported four changed
  claims. The script's own usage text promises this is "never a silent skip".

Implementation notes:
- Exit-code guidance re-keyed on output as well as code: 0-and-silent passes, 0-with-output is
  INFO-only findings, 1 is FAILs, 2 never ran.
- `parse_field_raw()` is line-based and joins continuation lines; `normalize_field_text()`'s
  docstring is now true rather than aspirational. A reorder deliberately fires: the two fields share
  one parser, and order-insensitivity would mean splitting a prose Description on commas.
- The discarded `show_err` is now surfaced as one whole-check INFO naming both readings.
- `--base-ref=` given empty now beats the env var, as the usage text always claimed.

`validate.sh` gains an ADR-0022 `metadata.version` check at FAIL tier, because any lower tier lets
skill-author Step 4 report done on a file the commit gate then refuses. Its `read` heuristic now
skips here-doc bodies — reflowing the one offending line would have cleared the finding and left
the cause, since every usage() heredoc is one wrap from putting the English verb in column 0.

Impact: provenance tests 73 -> 82, validate tests 64 -> 72. Test 72 previously deleted origin/main
before asserting the override, so it proved the flag works with no default rather than that it beats
one; it now moves origin/main forward first.

Refs: #118
ADR: 0022
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EeH8SCbcrCAQrtymkNuhKP

plugins/kyberforge/.apm/skills/skill-audit/README.md

@@ -11,7 +11,7 @@ Audit a skill directory against the agentskills.io specification and the house c
 
 `validate.sh` enforces two independent length families that must not be conflated: the agentskills.io spec conformance ceilings (500 lines, 2,770 words, both counting the whole file) and the ADR-0020 context budget (250/400 description characters, 600/900 body-only words).
 
-Alongside those it runs four shape checks that are not length measurements at all. Two are FAILs: every routing target named in the description — in the compressed `Not <thing> -> <name>` arrow **and** in the prose form — must resolve to a real skill or agent, and every `references/<file>.md` the body names must exist on disk. Three are SUGGESTIONs: a missing boundary clause, a Gotchas section over five entries, and a Gotchas section over 25% of the body. The resolution universe for boundary targets is derived by walking up from the audited `SKILL.md` — the authoring root above it, its own apm package, and that package's declared `apm.yml` dependencies — so a fresh clone and a machine that has run `apm install` return the same verdict. When no universe can be determined the check prints `INFO ... DID NOT RUN` and does not silently pass.
+Alongside those it runs shape checks that are not length measurements at all. Three are FAILs: every routing target named in the description — in the compressed `Not <thing> -> <name>` arrow **and** in the prose form — must resolve to a real skill or agent; every `references/<file>.md` the body names must exist on disk; and `metadata.version` must be present and three-part semver (ADR-0022). That last one is FAIL rather than SUGGESTION because the `skill-frontmatter` pre-commit hook rejects the file without it — an audit grading it lower would report ready-to-ship on a file the commit gate refuses. Three are SUGGESTIONs: a missing boundary clause, a Gotchas section over five entries, and a Gotchas section over 25% of the body. The resolution universe for boundary targets is derived by walking up from the audited `SKILL.md` — the authoring root above it, its own apm package, and that package's declared `apm.yml` dependencies — so a fresh clone and a machine that has run `apm install` return the same verdict. When no universe can be determined the check prints `INFO ... DID NOT RUN` and does not silently pass.
 
 ## Usage
 
@@ -26,8 +26,8 @@ Provide the path to the skill directory to audit when invoking.
 | File | Purpose |
 |------|---------|
 | `SKILL.md` | Skill instructions for agents |
-| `scripts/validate.sh` | Structural validator — checks name format, name matches directory, description presence and length, body-only word count, line and whole-file word ceilings, boundary-clause presence, boundary-target resolution, `references/` pointer existence, Gotchas entry count and body share, placeholder detection, script executable bit, and interactive-prompt detection |
-| `scripts/validate-provenance.sh` | Provenance validator — checks sources.md completeness, source_keys/slug consistency, Contributing files existence, bidirectional linkage, Research doc: fields, and upstream research doc alignment |
+| `scripts/validate.sh` | Structural validator — checks name format, name matches directory, description presence and length, `metadata.version` presence and semver shape (ADR-0022), body-only word count, line and whole-file word ceilings, boundary-clause presence, boundary-target resolution, `references/` pointer existence, Gotchas entry count and body share, placeholder detection, script executable bit, and interactive-prompt detection |
+| `scripts/validate-provenance.sh` | Provenance validator — checks sources.md completeness, source_keys/slug consistency, Contributing files existence, bidirectional linkage, Research doc: fields, upstream research doc alignment, and (check 9, INFO only) whether a slug's `Description` or `Contributing files` text has changed since a base ref — `--base-ref=<ref>` or `VALIDATE_PROVENANCE_BASE_REF`, defaulting to the merge base with `origin/main` |
 | `scripts/vale-wrap.sh` | Vale prefilter wrapper — runs the bundled `Kyberforge` Vale styles against SKILL.md and reports alerts as deterministic FAILs ahead of Step 3's qualitative review |
 | `assets/vale/.vale.ini` | Vale configuration — points Vale at the bundled `Kyberforge` style path, self-located relative to `vale-wrap.sh` |
 | `assets/vale/styles/Kyberforge/CompositionNote.yml` | Vale rule — flags composition and architecture notes in a description (e.g. "cross-cutting", "entry point", "rather than duplicating") |
@@ -41,7 +41,7 @@ Provide the path to the skill directory to audit when invoking.
 | `references/patterns.md` | Rubric for the patterns dimension — which instruction construct fits which job, and how each is correctly formed |
 | `references/file-structure.md` | Rubric for the file-structure and internal-consistency dimensions — permitted directories, cross-plugin path rules and their two structural exemptions, README drift |
 | `references/formatting-and-scripts.md` | Rubric for the formatting and scripts dimensions — heading and fencing conventions, and the agentic-use criteria for bundled scripts |
-| `references/validation-scripts.md` | Step 1 troubleshooting — the manual structural fallback when `validate.sh` cannot run, and the script exit codes that are easy to misread (loaded only on a script failure) |
+| `references/validation-scripts.md` | Step 1 troubleshooting — the manual structural fallback when `validate.sh` cannot run, and the script exit codes that are easy to misread (loaded on a script failure, and on any exit-0 run that printed something — `validate-provenance.sh`'s check 9 is INFO-only, so its findings arrive that way) |
 | `references/sources.md` | Provenance record — agentskills.io sources that informed this skill and which files each contributed to |
 | `tests/validate.bats` | (source-only) Bats test suite for validate.sh |
 | `tests/validate-provenance.bats` | (source-only) Bats test suite for validate-provenance.sh |