Add capture/triage inbox loop; dogfood AGENTS.md/ROADMAP; document git-tracking standard

Introduce the cross-project capture->triage->roadmap loop: /capture appends an
idea or bug to INBOX.md from any repo (new-project ideas included), /triage drains
a project's items into its AGENTS.md or ROADMAP.md. Give the standards repo its own
AGENTS.md (+ CLAUDE.md symlink) and ROADMAP.md so it follows its own standard, and
add a 'What git tracks' section to portability.md plus the canonical .gitignore
block answering what is committed vs gitignored around .claude and symlinks.

guides/triage.md

@@ -0,0 +1,70 @@
+# Triage — drain this project's inbox items into the right place
+
+You are running inside one project repo. Your job is to take the items in the cross-project
+inbox that belong to *this* repo and route each one to where it actually lives — then clear
+it from the inbox. This is the deliberate, with-context counterpart to `/capture`: capture
+is dumb and uniform, triage is where the judgment happens. Routing decisions are the user's
+call — propose, don't impose.
+
+The inbox is `~/Projects/standards/INBOX.md`. This repo is identified by its current working
+directory's folder name (and `AGENTS.md`/`README.md` if you need to confirm the name).
+
+## Procedure
+
+1. **Gather.** Read `~/Projects/standards/INBOX.md`. Select the unchecked items whose
+   `(project)` tag matches this repo's folder name. Also surface any `(?)` items and ask the
+   user whether each belongs to this repo — don't assume. **Never select `(new)` or
+   `(new:…)` items** — those are proposed new repos, not work for this one; if any exist,
+   note them in your report as awaiting the new-repo bootstrap, but leave them in the inbox.
+   If there are no matching items, say so and stop.
+2. **Orient.** Read this repo's `AGENTS.md` (especially `## Current state`) and `ROADMAP.md`
+   (if present) so your routing proposals fit what's already there and you can spot
+   duplicates of items already tracked.
+3. **Propose a routing for each item.** Present them as a short list, each with a proposed
+   destination and a one-line reason. The destinations:
+   - **`## Current state` in AGENTS.md** — near-term, act-on-it-now items (high priority,
+     active work, a bug to fix this session).
+   - **`ROADMAP.md`** — longer-term backlog (features, ideas, deferred work). Create
+     `ROADMAP.md` if it doesn't exist and there's anything to put there.
+   - **A `docs/guides/<topic>.md`** (or this repo's equivalent guide location) — if the
+     item is durable subsystem guidance rather than a task.
+   - **Escalate to the standards repo** — if the item is really a cross-repo idea (a new
+     command/agent/standard), it belongs in the standards `ROADMAP.md` or stays in the
+     inbox tagged `(standards)`, not in this project. Flag these; don't force them into the
+     project.
+   - **Discard** — already done, duplicate, or no longer wanted. Say why.
+   Let the captured priority (`Pn`) inform the destination but use judgment — a `P1` bug
+   goes to Current state, a `P3` idea to ROADMAP.
+4. **Get approval.** Wait for the user to confirm or adjust the routing. Do not edit any
+   file before they approve — these are their durable project files.
+5. **Apply.** Make the approved edits to this repo's files (keep `## Current state` lean —
+   present tense, ~15 lines max per the close-out convention; if it overflows, push older
+   items to ROADMAP). Then remove the triaged items from `~/Projects/standards/INBOX.md` — delete the
+   lines outright (the git history is the record); leave untriaged and other-repo items
+   untouched.
+6. **Commit.** Two repos changed — present the proposed commit message(s) for both and
+   **wait for the user to confirm before committing or pushing anything** (the same gate as
+   step 4): this project's AGENTS.md/ROADMAP changes, and the standards repo's INBOX.md
+   (`git -C ~/Projects/standards …`). Follow `how-i-work.md` for messages and the
+   no-AI-attribution rule.
+7. **Report** what landed where, what was discarded, and any items escalated to the
+   standards repo that the user still needs to handle there.
+
+## The portable inbox-check line
+
+So pending items surface automatically at the *start* of a session (not only when the user
+remembers to run `/triage`), every project repo's `AGENTS.md` should carry this line — it's
+vendor-neutral, so any harness that reads AGENTS.md honors it:
+
+> **Inbox check:** At session start, if `~/Projects/standards/INBOX.md` exists, scan it for
+> items tagged `(this-repo)` and surface them before proposing next steps; triage with
+> `/triage`.
+
+If this repo's AGENTS.md lacks that line, offer to add it as part of the triage.
+
+## Rules
+
+- Never invent items or routings. If an item is ambiguous, ask.
+- Never edit a project file before the user approves the routing.
+- If you cannot read `~/Projects/standards/INBOX.md`, stop and report precisely that — do
+  not guess what was captured.