refactor(skills): mandate metadata.version on every skill's frontmatter

Only 12 of 39 skills carried metadata.version, and adoption tracked
which plugin a skill lived in rather than any stated rule: core,
gitea and lint were consistent adopters, bin and kyberforge were
consistent non-adopters, git was split with one outlier. There was
no documented convention, and skill-author's own bump logic was
already written as if presence were conditional.

metadata.version is now required on every skill. The 19 skills here
that never carried one (bin, kyberforge, gitea-files) are seeded at
1.0.0, not 0.1.0 -- that value stays reserved for a skill's actual
creation point under skill-author's existing convention. The
skill-frontmatter pre-commit hook now fails a SKILL.md missing the
field, the same class of failure as a missing name/description.

Full rationale in the new ADR. The git-plugin skills that also need
this field follow in the next commit, bundled with issue #113's rtk
normalization since both touch the same files.

Refs: #127
ADR: 0022
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EeH8SCbcrCAQrtymkNuhKP

plugins/bin/.apm/skills/caveman/SKILL.md

@@ -4,6 +4,8 @@ disable-model-invocation: true
 description: >
   Ultra-compressed output mode that drops articles, filler and pleasantries while
   keeping technical substance exact, cutting token usage by roughly 75%.
+metadata:
+  version: "1.0.0"
 ---
 
 Respond terse like smart caveman. All technical substance stay. Only fluff die.

plugins/bin/.apm/skills/diagnose/SKILL.md

@@ -4,6 +4,8 @@ description: >
   Use when the user says "diagnose this" or "debug this", reports something
   broken, throwing, or failing, or says something got slow. Not filing or
   triaging a reported bug -> `triage`. Not test-first feature work -> `tdd`.
+metadata:
+  version: "1.0.0"
 ---
 
 # Diagnose

plugins/bin/.apm/skills/grill-me/SKILL.md

@@ -5,6 +5,8 @@ description: >
   relentless interview — one question at a time, down each branch of the
   decision tree. Not a plan to challenge against `CONTEXT.md` and ADRs ->
   `grill-with-docs`.
+metadata:
+  version: "1.0.0"
 ---
 
 Interview me relentlessly about every aspect of this plan until we reach a shared understanding. Walk down each branch of the design tree, resolving dependencies between decisions one-by-one. For each question, provide your recommended answer.

plugins/bin/.apm/skills/grill-with-docs/SKILL.md

@@ -4,6 +4,8 @@ description: >
   Use when a plan should be stress-tested against the project's domain model —
   the interview challenges terms against `CONTEXT.md` and writes decisions into
   it and into ADRs as they land. Not a plain interview -> `grill-me`.
+metadata:
+  version: "1.0.0"
 ---
 
 <what-to-do>

plugins/bin/.apm/skills/improve-codebase-architecture/SKILL.md

@@ -6,6 +6,8 @@ description: >
   testable and AI-navigable — deepening opportunities that turn shallow modules
   into deep ones, informed by `CONTEXT.md` and `docs/adr/`. Not debugging a
   failure -> `diagnose`.
+metadata:
+  version: "1.0.0"
 ---
 
 # Improve Codebase Architecture

plugins/bin/.apm/skills/prototype/SKILL.md

@@ -5,6 +5,8 @@ description: >
   a data model, state machine or business logic, or to mock up a UI in several
   variations. Not production code -> `tdd`. Not talking a design through ->
   `grill-me`.
+metadata:
+  version: "1.0.0"
 ---
 
 # Prototype

plugins/bin/.apm/skills/research/SKILL.md

@@ -6,6 +6,7 @@ description: >-
   documentation written from existing code or specs -> `write-docs`. Not a bug
   or incident -> `diagnose`.
 metadata:
+  version: "1.0.0"
   category: research
 allowed-tools:
   - Grep

plugins/bin/.apm/skills/tdd/SKILL.md

@@ -4,6 +4,8 @@ description: >
   Use when the user wants a feature built or a bug fixed test-first, in a strict
   red-green-refactor loop, one behaviour at a time. Not diagnosing an existing
   bug -> `diagnose`. Not throwaway exploratory code -> `prototype`.
+metadata:
+  version: "1.0.0"
 ---
 
 # Test-Driven Development

plugins/bin/.apm/skills/triage/SKILL.md

@@ -4,6 +4,8 @@ description: >
   Use when the user wants an issue created, triaged, or moved through the
   tracker's triage states, or an issue prepared for an AFK agent. Not debugging
   the bug itself -> `diagnose`. Not fleshing out a design -> `grill-with-docs`.
+metadata:
+  version: "1.0.0"
 ---
 
 # Triage

plugins/bin/.apm/skills/write-docs/SKILL.md

@@ -6,10 +6,10 @@ description: >
   module", "create docs for this feature", "write a README for this". Not an ADR
   or other decision record -> `grill-with-docs`. Not an external tool researched
   from its docs -> `research`.
-version: "1.0"
 updated: 2026-05-17
 when: invoked by explicit trigger ("write docs for X", "document this module", "create docs for this feature") or implicit request to produce technical documentation from code or spec
 metadata:
+  version: "1.0"
   category: implement
 source:
   - repo: anthropics/skills

plugins/bin/.apm/skills/zoom-out/SKILL.md

@@ -2,6 +2,8 @@
 name: zoom-out
 description: Tell the agent to zoom out and give broader context or a higher-level perspective. Use when you're unfamiliar with a section of code or need to understand how it fits into the bigger picture.
 disable-model-invocation: true
+metadata:
+  version: "1.0.0"
 ---
 
 I don't know this area of code well. Go up a layer of abstraction. Give me a map of all the relevant modules and callers, using the project's domain glossary vocabulary.