ai(rules[AGENTS]) Shipped vs. Branch-Internal Narrative breaker

why: Roll out the narrative-bleed guard rule (defined in
tony/ai-workflow-plugins#15) so every project in the portfolio
shares the same "shipped artifacts hold current state; commits
hold history" discipline and the same Published-Release Test
diagnostic.

what:
- Add the Shipped vs. Branch-Internal Narrative section to
  AGENTS.md.
- For repos that did not have AGENTS.md, create it with a minimal
  header.

Refs tony/ai-workflow-plugins#15

Author: tony

AGENTS.md

@@ -507,3 +507,60 @@ When stuck in debugging loops:
 2. **Minimize to MVP**: Remove all debugging cruft and experimental code
 3. **Document the issue** comprehensively for a fresh approach
 4. **Format for portability** (using quadruple backticks)
+
+## Shipped vs. Branch-Internal Narrative
+
+Long-running branches accumulate tactical decisions — renames,
+refactors, attempts-then-reverts, intermediate states. Commit messages
+and the diff hold *what changed* and *why*. Do not restate either in
+artifacts the downstream reader holds: code, docstrings, README,
+CHANGES, PR descriptions, release notes, migration guides.
+
+When deciding what counts as branch-internal, use trunk or the parent
+branch as the baseline — not intermediate states inside the current
+branch.
+
+**The Published-Release Test**
+
+Before adding rename history, "previously" / "formerly" / "no longer
+X" phrasing, "removed" / "moved" / "refactored" / "fixed" diff
+paraphrases, or `### Fixes` entries to a user-facing surface, ask:
+
+> Did users of the most recently published release ever experience
+> this old name, old behavior, or bug?
+
+If the answer is no, it is branch-internal narrative. Move it to the
+commit message and describe only the current state in the artifact.
+
+**Keep in shipped artifacts**
+
+- Deprecations and migration guides for symbols that actually shipped.
+- `### Fixes` entries for bugs that affected users of a published
+  release.
+- Comments explaining *why the current code looks this way* —
+  invariants, platform quirks, upstream bug workarounds — that make
+  sense to a reader who never saw the previous version.
+
+**Default**: when in doubt, keep the artifact clean and put the story
+in the commit.
+
+### Cleanup in Hindsight
+
+When applying this rule retroactively from inside a feature branch,
+first establish scope by diffing against the parent branch (or trunk)
+to identify which commits this branch actually introduced. Then:
+
+- **Commits introduced in this branch** — prompt the user with two
+  options: `fixup!` commits with `git rebase --autosquash` to address
+  each causal commit at its source, or a single cleanup commit at
+  branch tip. User chooses.
+- **Commits already in trunk or a parent branch** — default to
+  leaving them alone. Do not raise them as cleanup candidates; act
+  only on explicit user instruction. If the user opts in, fold the
+  cleanup into a single commit at branch tip and do not rewrite trunk
+  or parent-branch history.
+- **Scope guard** — if cleaning in-branch bleed would touch a
+  colleague's in-flight work or expand the branch beyond its stated
+  goal, default to staying in lane: protect the project's current
+  goal, leave prior bleed alone, and don't introduce new bleed in the
+  current change.