Thread inbox-check line and canonical .gitignore into the retrofit flow; scope relative-symlink rule to in-repo links

Retrofit playbook Step 0/Step 1 and the /retrofit guide now seed every new repo
with the canonical .gitignore block and the inbox-check line, and Part 5 documents
/capture, /triage, /roundup. portability.md and the portability-checker guide now
scope the relative-symlink mandate to in-repo (committed) symlinks, so global
~/.claude/* links are no longer flagged. ROADMAP adds a high-priority cross-repo
git-hygiene audit.

guides/retrofit.md

@@ -22,8 +22,9 @@ guess on anything that changes what lands on disk.
 
 ## Phase 1 — Git audit (playbook Step 0)
 
-- If this is not a git repo: propose `git init`, a sensible `.gitignore` (including
-  `.env`), and an initial commit. Get approval before running.
+- If this is not a git repo: propose `git init`, a `.gitignore` (the canonical block from
+  `portability.md`'s "What git tracks" — `.env`, `.claude/settings.local.json` and
+  `*.local.*`, OS cruft), and an initial commit. Get approval before running.
 - If it is: report whether there are uncommitted changes and when the last commit was,
   then propose committing anything outstanding (a repo existing isn't the same as work
   being saved — uncommitted changes are as unprotected as no repo at all).
@@ -88,6 +89,8 @@ AGENTS.md now exists but is a strong draft, not yet checked against reality.
 - **Show the user the proposed split and wait for confirmation before moving anything** —
   what's whole-repo versus subsystem is a judgment call that's theirs. Then report what
   moved where.
+- Ensure AGENTS.md carries the **inbox-check line** (the portable surfacing mechanism; see
+  `retrofit-playbook.md` Step 1 / `portability.md`). If it's missing, propose adding it.
 
 ## Phase 5 — Independent checks (delegate)