refactor(skills): retrofit the corpus to the ADR-0020 context contract (#129)

Retrofits all 39 skills to ADR-0020's description/body context contract, then fixes what six rounds of independent review found in that retrofit — including four ways the hot gate itself failed open.

Closes #99, #107, #108, #110, #111, #114, #115, #120.

## The retrofit (waves 1-5)

| | Start | Now |
|---|---|---|
| Description FAILs (>400 chars) | 26 | **0** |
| Body FAILs (>900 words, body-only) | 9 | **0** |
| Dangling routing targets | 2 | **0** |
| `Kyberforge.CompositionNote` | 10 | **0** |
| Preload tax | 21,005 chars | **~10,500** |

Under the 12,000-char success criterion. Per-wave detail is on #99.

## The review fixes

**The gate failed open four ways, three of them found after the retrofit shipped.** An unrecognised follower token made a dangling target vanish. A skill directory with no `SKILL.md` resolved as a valid target, so a commit could be green locally and red in a fresh clone — three existing fixtures were relying on that, one of which made the install-leak A/B pass vacuously. Then the free-standing `/name` sweep turned out to be gated on the sentence carrying a boundary marker, so route notation in any other sentence was invisible — not an ERROR, not a SUGGESTION, not an INFO — which left the documented "`/name` always blocks" promise false from a second direction. All four fixed and pinned.

**Two checks were silently not running.** `validate-provenance.sh` checks 7-8 were dead across nine skills. Waking them exposed a deeper problem: they assume `Research doc:` names a source index, but 30 of 121 entries point at topic content documents, so every new check-7 INFO was a false positive and check 8 was saved from a false-FAIL flood only by an *unannounced* skip. Checks 7/8 are now scoped to source indexes and every skip announces itself (#121).

**The retrofit's own anti-goal, four times.** ADR-0020 warns that a blunt gate gets satisfied by deleting content rather than relocating it. `diagnose` and `skill-audit` relocated prose and then read it unconditionally; `prototype` and `vale-config` deleted rules outright that survived nowhere. All four addressed.

## Verification

- `bash tests/run-tests.sh --strict` — 24 suites, 0 skipped, 0 failed
- `bash tests/run-bats.sh` — 325 tests, 0 failures
- `pre-commit run --all-files` — 17/17
- `pre-commit run --hook-stage pre-push --all-files` — 16/16, with `apm marketplace check` and `apm pack --check-clean` run against the remote, not skipped
- `scripts/skill-size-check.sh` over all 39 skills — rc 0, 0 ERROR/FAIL, SUGGESTION-only
- Preload tax measured at **10,498 chars**, max description 390 — both inside budget
- Every new test proven non-vacuous by a deliberate mutation of the behaviour it covers

**Per-commit sync, stated accurately:** the ten commits from the latest review round each pass `check-plugin-content-sync` in isolation, verified by checking each out in a detached worktree with a clean between. The earlier gitea window (`dfacf05..bedbd1d`, nine commits) does **not** — its mirror was regenerated in one batch at `bbc7300`. An earlier revision of this description claimed the property held for every commit; it does not, and a bisect through that window lands on a red commit. **Squash-merge** to collapse it, or accept that this range is not bisectable.

## Version bump

Six plugins and the catalog take a **patch**, not a minor. The branch is **89 commits — 40 `fix` / 30 `refactor` / 12 `docs` / 5 `chore` / 2 `test` — zero `feat`, zero `!`, zero `BREAKING CHANGE`** — and adds no skill, agent, command or hook. (Two earlier revisions of this section cited a stale histogram, most recently 78 commits; the figures above are measured at HEAD.) Both rules this repo ships (`forge/references/version-bump.md`, landing in this PR, and `git-commits/references/conventional-commits-spec.md`) make that a patch, and the catalog set is unchanged at 7 entries.

Not settled by that: four published files were removed from the installed tree, three moved, and `caveman` gained `disable-model-invocation`, retiring its old triggers. Under a strict reading those are major-class and currently ship under `refactor:` with no marker. Whether the deployed skill surface is a public contract is written down nowhere — worth deciding, but it outlives this PR.

## Deliberately not in scope

#112 (cherry-pick ownership, now resolved in favour of `git-commits`), #113 (`rtk git` normalisation), #116 (research fan-out), #101 (audit-skill merge), #122 (non-spec skill-root files), #123 (no PRD producer) stay open. #117 is the one worth reading: the contract's remedy is to move prose into `references/`, which is exactly where neither the size gate nor Vale looks — and the blind spot is wider than #117 currently records, since there is no root `.vale.ini` at all, so every ADR, `CONTEXT.md` and `README.md` is unlinted too.

That blind spot let this branch carry two `level: error` `Kyberforge.SentenceOpenerThereIs` violations into `references/` files it created — `provider-adapter-author/references/provider-matrix.md:31` and `agent-audit/references/finding-criteria.md:95`. Both are reworded in `afadaae`, confirmed by routing each file through the audit's own `vale-wrap.sh` (1 error each before, 0 after). Five further occurrences sit in `references/` files already on `main`; those are the pre-existing corpus and stay with #117, which is the real fix.

Also unfixed and not this PR's: `apm install` appends a duplicate `SessionStart` entry to `.claude/settings.json`, so a fresh clone cannot get pre-push green without an edit AGENTS.md warns against. Reproduces identically on `main`.

Co-authored-by: Defame1297 <gitea@rkdr.net>
Reviewed-on: https://git.dev.rkdr.net/Defame1297/holocron/pulls/129
Co-authored-by: Claude Code AI - Gitea MCP <claude@noreply.git.dev.rkdr.net>
Co-committed-by: Claude Code AI - Gitea MCP <claude@noreply.git.dev.rkdr.net>

plugins/git/.apm/skills/git-branches/references/branch-operations.md

@@ -0,0 +1,56 @@
+---
+source_keys:
+  - context7-git-htmldocs
+---
+
+# Per-action command mapping
+
+One command per action. Where two forms exist, the first is the default and the second the escape
+hatch.
+
+- **create** — `git switch -c <branch> <base>`. Base comes from the config's `base_branch`
+  (`main` under GitHub Flow, usually `develop` under Gitflow).
+- **switch** — `git switch <branch>` moves to an existing local branch; it aborts rather than
+  clobbering conflicting local changes. `git switch -` returns to the previous branch.
+- **delete (local)** — `git branch -d <branch>` refuses when the branch holds unmerged commits,
+  which is why it is the default. `git branch -D <branch>` forces the deletion and discards that
+  work — only after the destructive-operation gates pass and `confirm: true` is set.
+- **delete (remote)** — not this skill's. Deleting a remote branch is a push, and every remote-side
+  gate lives in `git-remotes`; hand it there rather than running the push from here. Its
+  `references/push.md` carries the command and the refspec form.
+- **rename** — `git branch -m <old> <new>`.
+- **list** — `git branch` (local), `-a` (local plus remote-tracking), `-r` (remote-tracking only),
+  `--merged` / `--no-merged` (filter by merge status into the current branch).
+- **track** — `git branch --set-upstream-to=origin/<branch>` sets an upstream without pushing.
+  `git branch -vv` shows the tracking state of every local branch.
+
+## get-intent
+
+Git has no native field for free-text branch metadata, and this skill does not persist any. On
+`create`, the `intent` value is only returned in the structured result — the caller decides
+whether to store it.
+
+On `get-intent`, either parse the intent back out of the branch-name convention
+(`feature/<intent-slug>`) or return `{ "intent": null }` when the caller never persisted the
+create-time value. Never fabricate an intent: a downstream commit message built on a guessed
+intent is worse than one built on none.
+
+## Stashing work in progress
+
+A switch aborts rather than clobbering conflicting local changes (see Gotchas). Stash is the way
+past it: it shelves the working tree and index so the branch pointer can move.
+
+- **save** — `git stash push -m "<message>"`. Add `-u` to include untracked files; verified on Git
+  2.39.5, a plain `push` leaves them in place, and a plain `push` with *only* untracked changes
+  reports `No local changes to save` and stashes nothing. Bare `git stash` is `push` with no message.
+- **restore** — `git stash pop` applies the newest entry and deletes it. `git stash apply stash@{n}`
+  applies without deleting, for replaying one shelf onto more than one branch.
+- **list** — `git stash list`; `git stash show -p stash@{n}` prints that entry's diff.
+- **drop** — `git stash drop stash@{n}` deletes one entry. `git stash clear` deletes all of them
+  and nothing recovers them — confirm before running it.
+- **branch from a stash** — `git stash branch <branch> stash@{n}` creates a branch at the commit the
+  stash was taken from and pops it there. Use it when the stash no longer applies to the current tip.
+
+**A conflicting `pop` keeps the entry.** Verified on 2.39.5: it exits 1, writes conflict markers,
+prints "The stash entry is kept in case you need it again", and `git stash list` still shows it.
+Resolve, `git add`, then `git stash drop` the entry by hand — otherwise it silently accumulates.

plugins/git/.apm/skills/git-branches/references/branch-patterns.md

@@ -0,0 +1,31 @@
+---
+source_keys:
+  - nvie-gitflow-post
+  - atlassian-gitflow-tutorial
+  - gitflow-cheatsheet
+---
+
+# Branch patterns
+
+Which pattern is in play decides the base branch, the branch name prefix, and whether merges are
+allowed to fast-forward. Default to GitHub Flow — simpler, and what CI/CD-oriented repos expect.
+Fall back to Gitflow only when the config says so or the repo already carries `develop` or
+`release/*` branches.
+
+## GitHub Flow
+
+- Base: `main`
+- Feature branches: `feature/<feature-name>` or `fix/<bug-name>`
+- Merge: fast-forward where possible, to keep history linear
+- Delete the branch after merge
+
+## Gitflow
+
+- Base: `main` (production) plus `develop` (integration)
+- Feature branches: `feature/<feature-name>`, cut from `develop`
+- Release branches: `release/X.Y.Z`, cut from `develop`, merged to both `main` and `develop`
+- Hotfix branches: `hotfix/X.Y.Z`, cut from `main`, merged to both `main` and `develop`
+- Merge: always `--no-ff`, so the branch structure survives in the history
+
+The two are not mixable. A `--no-ff` merge into a GitHub Flow repo leaves merge commits nobody
+expects; a fast-forward merge of a Gitflow release branch erases the release boundary.

plugins/git/.apm/skills/git-branches/references/comparing-branches.md

@@ -0,0 +1,16 @@
+---
+source_keys:
+  - context7-git-htmldocs
+---
+
+# Comparing two branches
+
+The two-dot and three-dot forms mean different things and are easy to swap by accident — check the
+direction before reporting a result.
+
+- `git log main..feature` — commits on `feature` that are not on `main`.
+- `git log feature..main` — the reverse direction: commits on `main` not on `feature`.
+- `git log --left-right main...feature` — both diverging sets at once (symmetric difference).
+- `git diff main...feature` — the diff from the common ancestor to `feature`'s tip, which is what
+  a reviewer sees, rather than the diff between the two tips.
+- `git merge-base main feature` — print the common ancestor commit.

plugins/git/.apm/skills/git-branches/references/merging.md

@@ -0,0 +1,30 @@
+---
+source_keys:
+  - context7-git-htmldocs
+  - atlassian-gitflow-tutorial
+---
+
+# Merging one branch into another
+
+Scope is fast-forward and merge-commit mechanics plus conflict resolution. Rebase and cherry-pick
+belong to `git-commits`; revert to `git-history`.
+
+- **Fast-forward** — `git merge <branch>` advances the pointer with no merge commit when the
+  target has not diverged.
+- **True merge** — `git merge --no-ff <branch>` forces a merge commit even when a fast-forward is
+  possible. Gitflow requires it on every supporting-branch merge.
+- **Squash merge** — `git merge --squash <branch>` stages the combined diff without committing.
+  Follow it with a `git commit`.
+- **Octopus merge** — `git merge branch-a branch-b branch-c` merges more than two branches at
+  once, but fails outright on any conflict. Use sequential two-way merges when conflicts are
+  likely.
+
+## Conflict resolution
+
+When Git cannot auto-merge it writes conflict markers and stops mid-merge. Run `git status` to
+list the conflicted files, edit each to resolve its markers, then `git add <file>` and
+`git merge --continue`.
+
+- `git merge --abort` restores the pre-merge state.
+- `git mergetool` opens the configured merge tool.
+- `git diff --diff-filter=U` shows only the still-conflicted files.

plugins/git/.apm/skills/git-branches/references/orchestrator-contract.md

@@ -0,0 +1,20 @@
+---
+source_keys: []
+---
+
+# Orchestrator request contract
+
+`git-orchestrate` and other calling agents send this shape. The result shape they parse back is in
+`SKILL.md` Step 5, because every run emits one.
+
+Request:
+
+```json
+{
+  "action": "create|switch|delete|rename|track|list|get-intent",
+  "branch": "<branch-name>",
+  "base": "<base branch, optional, defaults to config>",
+  "intent": "<human-readable intent, optional>",
+  "confirm": "<true for destructive ops, omit for read ops>"
+}
+```

plugins/git/.apm/skills/git-branches/references/sources.md

@@ -12,7 +12,8 @@
 - **Research doc:** plugins/git/docs/research/docs/git/gitflow.md (whole-document reference)
 
 **Contributing files:**
-- SKILL.md (Branch Patterns — Gitflow vs. GitHub Flow structure and defaults)
+- SKILL.md (Gitflow vs. GitHub Flow inference and the not-mixable rule)
+- references/branch-patterns.md (Gitflow vs. GitHub Flow structure, defaults, and why the two are not mixable)
 
 ## atlassian-gitflow-tutorial
 
@@ -23,7 +24,9 @@
 - **Research doc:** plugins/git/docs/research/docs/git/gitflow.md (whole-document reference)
 
 **Contributing files:**
-- SKILL.md (Branch Patterns — Gitflow branch types, base/merge targets, `--no-ff` requirement)
+- SKILL.md (Gitflow vs. GitHub Flow inference and the not-mixable rule)
+- references/branch-patterns.md (Gitflow branch types, base/merge targets, `--no-ff` requirement)
+- references/merging.md (`--no-ff` requirement on Gitflow supporting-branch merges)
 
 ## gitflow-cheatsheet
 
@@ -34,7 +37,7 @@
 - **Research doc:** plugins/git/docs/research/docs/git/gitflow.md (whole-document reference)
 
 **Contributing files:**
-- SKILL.md (Branch Patterns — feature/release/hotfix naming conventions)
+- references/branch-patterns.md (feature/release/hotfix naming conventions)
 
 ## context7-git-htmldocs
 
@@ -45,4 +48,7 @@
 - **Research doc:** plugins/git/docs/research/docs/git/branching-merging.md (whole-document reference)
 
 **Contributing files:**
-- SKILL.md (Command mapping, Merging, Comparing Branches — `git switch`/`git branch`/`git merge`/`git log`/`git diff`/`git merge-base` command vocabulary and flags)
+- SKILL.md (Gotchas — `git switch` abort-on-conflict behaviour, branch/tag name ambiguity)
+- references/branch-operations.md (`git switch`/`git branch` command vocabulary and flags)
+- references/merging.md (`git merge` strategies and conflict-resolution commands)
+- references/comparing-branches.md (`git log`/`git diff`/`git merge-base` range syntax)