fix(git): stop prefixing rtk where it rewrites the output skills parse

The #113 sweep rested on CLAUDE.md's premise that rtk either filters or passes through unchanged,
so prefixing is always safe. Measured against rtk 0.42.4, that premise is false for several of the
commands the sweep prefixed, and two skills were left giving wrong answers silently.

Why:
- `rtk git worktree list --porcelain -z` discards both flags and renders its own format. The
  `locked`/`lock_reason` fields git-worktrees Step 2 must emit are absent entirely, and paths under
  $HOME are abbreviated to `~/`.
- `rtk git branch --list <name>` prints a phantom `* ` line even when nothing matches, so
  git-branches' stated ambiguity test — "output from both means the name is ambiguous" — reported
  every name as ambiguous. `tag --list` is a clean passthrough, so only one half broke.
- `rtk git diff --name-only`/`--name-status` append a `Changes:` trailer to output documented as
  "one per line"; `--word-diff` emits none of the `[-removed-] {+added+}` markers its table
  describes; `rtk git log -L` truncates each line at ~72 chars, on the one command whose purpose is
  showing line content.
- `rtk git stash pop` prints only `FAILED: git stash pop`, swallowing the conflict diagnostic and
  retained-entry message the surrounding prose tells the agent to rely on.

Implementation notes:
- Eleven sites reverted to bare `git`, each carrying its reason inline so the next sweep does not
  undo it. `mergetool` and `rebase -i` are reverted on clause 3's interactive limb only: the TTY
  defect does not reproduce — rtk filters exactly twelve subcommands and execs the rest — and
  ADR-0023 records that measurement rather than a convenient one.
- ADR-0023 states the rule repo-wide with a third clause: a command whose output the skill parses,
  or which is interactive, stays bare. `plugins/git/README.md` is reduced to a pointer; its claim
  that gitea skills "contain no git/rtk mentions at all" was false, and its citation of
  `hard-rules.md` pointed at a file containing no occurrence of "rtk".
- Eight gitea sites swept, all verified byte-identical passthroughs first.
- `scripts/check-rtk-prefix.sh` gates clause 1. Run against main's pre-sweep corpus it reports 99
  findings including every gitea site, so it would have caught the drift #113 was filed about.

Impact: the gate covers clause 1 only, in shell-tagged fences and the opening span of Run cells.
Clause 2 is not gateable — "Run `git switch`" and "`git switch` refuses" are the same tokens — and
prose bullets are invisible to it. Both limits are recorded in gates.md rather than left implied.

Refs: #113
ADR: 0023
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EeH8SCbcrCAQrtymkNuhKP

plugins/git/README.md

@@ -30,12 +30,9 @@ copilot plugin install ./plugins/git
 
 ## Conventions
 
-Every skill in this plugin runs local git commands through the org's `rtk` wrapper, never bare `git` — see `git-commits/SKILL.md`'s Gotchas and `git-workflow/references/hard-rules.md`. Issue #113 made that rule precise for skill *prose*, where a `git <subcommand>` mention can be either an instruction to execute or just a reference to the concept:
+Skills here run local git commands through the org's `rtk` wrapper. **When a command is prefixed, when it stays bare, and why some executable commands must stay bare are all decided by ADR-0023** (`docs/adr/0023-rtk-prefix-marks-executable-commands-only.md`), which is repo-wide and not specific to this plugin. `check-rtk-prefix` enforces the part of it that is machine-decidable.
 
-- **Executable, instructed commands** — anything telling the agent to run a command right now (an imperative step, a dispatch-table "Run" cell, a fenced code-block procedure) — use `rtk git`. Example: `rtk git push -u origin <branch>`.
-- **Illustrative or referential mentions** — naming a flag's behavior, quoting a doc's own heading, describing what a command does in the abstract, or warning against an anti-pattern — stay bare `git`. Example: "`git switch` refuses rather than clobbering conflicting local edits."
-
-This applies within this plugin's own skill files (`git-*`, `pc-*`) — it does not generalize to other plugins. The `gitea-*` skills, for instance, talk to a remote Gitea server through the `gitea` MCP tools and contain no `git`/`rtk` mentions at all; the distinction has nothing to hold onto there.
+Installing this plugin without `rtk`? Every prefixed command is a plain `git` invocation with a word in front of it — drop the `rtk ` and it is correct.
 
 ## Contents