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/.apm/skills/git-history/references/git-log-format.md

@@ -161,11 +161,15 @@ rtk git log --diff-filter=M        # only show commits with modified files
 
 Traces the evolution of a specific range of lines or a named function through commits. Implies `--patch`.
 
+Bare `git`, not `rtk git`, on every `-L` form below: rtk truncates each diff body
+line at roughly 72 characters with an ellipsis, on the one query whose whole point
+is showing line content.
+
 ```bash
-rtk git log -L 10,20:file.txt
-rtk git log -L /start_pattern/,/end_pattern/:file.txt
-rtk git log -L :myfunction:src/app.c
-rtk git log -L /init/,+15:config.py          # 15 lines after first match of /init/
+git log -L 10,20:file.txt                          # bare per ADR-0023
+git log -L /start_pattern/,/end_pattern/:file.txt  # bare per ADR-0023
+git log -L :myfunction:src/app.c                   # bare per ADR-0023
+git log -L /init/,+15:config.py                    # bare per ADR-0023; 15 lines after first /init/ match
 ```
 
 Range formats:
@@ -205,20 +209,26 @@ rtk git diff --numstat                # machine-readable: <added>\t<deleted>\t<p
 
 ### --name-only / --name-status
 
+Bare `git`, not `rtk git`: rtk appends a blank line and a `Changes:` trailer, so
+the output is no longer one record per line.
+
 ```bash
-rtk git diff --name-only              # only filenames, one per line
-rtk git diff --name-status            # status letter + filename per line
+git diff --name-only      # bare per ADR-0023; only filenames, one per line
+git diff --name-status    # bare per ADR-0023; status letter + filename per line
 ```
 
 `--name-status` uses the same status letters as `--diff-filter`.
 
 ### --word-diff
 
+Bare `git`, not `rtk git`: rtk replaces the word-diff with its own diffstat
+renderer and emits none of the `[-removed-] {+added+}` markers.
+
 ```bash
-rtk git diff --word-diff              # inline word-level diff with [-removed-] {+added+} markers
-rtk git diff --word-diff=color        # color only, no markers
-rtk git diff --word-diff=porcelain    # machine-readable: +/- prefixed lines, ~ for newlines
-rtk git diff --word-diff-regex=<re>   # define what counts as a "word"
+git diff --word-diff             # bare per ADR-0023; inline word-level diff, [-removed-] {+added+} markers
+git diff --word-diff=color       # bare per ADR-0023; color only, no markers
+git diff --word-diff=porcelain   # bare per ADR-0023; machine-readable: +/- prefixed lines, ~ for newlines
+git diff --word-diff-regex=<re>  # bare per ADR-0023; define what counts as a "word"
 ```
 
 ### Whitespace Flags