docs: align README + governance docs with current state (uninstall, files, ADR index, ship-archive) (#59)

Multiple documentation polish items rolled into one PR (one layer:
"docs alignment with current state").

### README.md

- **Uninstall section** added between Server Setup and Client Setup
  (was missing — `node uninstall.mjs` exists but went undocumented).
- **OpenClaw definition** added as a footnote on first README mention
  (the architecture diagram and Supported Tools table both reference
  OpenClaw without ever defining it).
- **Repository Layout section** added before Security — table of
  top-level files (server.mjs, setup.mjs, uninstall.mjs, keys.mjs,
  models.json, ocp/ocp-connect, dashboard.html, scripts/, .claude/skills/,
  ocp-plugin/, docs/adr/, ALIGNMENT.md, AGENTS.md, CLAUDE.md) so a new
  contributor knows what each file does.
- **LICENSE link** added to the License section footer.

### docs/adr/README.md (new)

- Index of the three published ADRs (0002, 0003, 0004) with a one-line
  description each.
- Explains the `0001` placeholder (early internal proposal that was
  superseded; numbering deliberately starts at `0002`).
- Guidance on when to write a new ADR vs. when a commit message suffices.

### Spec/plan housekeeping

- `specs/.gitkeep` removed (the empty `specs/` placeholder confused the
  picture; canonical paths are `docs/superpowers/plans/` for active plans
  and `docs/superpowers/specs/` for long-lived design docs that other
  code references).
- Shipped plans moved to `docs/superpowers/plans/shipped/`:
  - `2026-04-10-lan-mode.md` (shipped: README LAN mode section)
  - `2026-04-25-47-sse-heartbeat-plan.md` (shipped: v3.12.0 per CHANGELOG)
- `2026-04-25-47-sse-heartbeat-design.md` left in `docs/superpowers/specs/`
  unchanged because both `server.mjs:565` and `CHANGELOG.md:7` link to
  that exact path; moving it would require a `server.mjs` edit, which
  needs `cli.js` citation per ALIGNMENT.md Rule 1.

### AGENTS.md

- Updated "Key files to know" to add `docs/adr/README.md`,
  `docs/superpowers/plans/`, and `memory/constitution.md`.
- Note explaining `memory/constitution.md` is spec-kit's standard
  location, distinct from `~/.cc-rules/memory/` and `ALIGNMENT.md`.
- Updated "Handoff expectations" item 5 from `docs/superpowers/specs/*/tasks.md`
  (which never matched anything — there were no `tasks.md` files there)
  to `docs/superpowers/plans/` (excluding `shipped/`).

### Coordination with PR #53

PR #53 is open and adds "Why OCP?", "Comparison", and "Governance"
sections to README. This PR deliberately avoids those areas — only edits
the Supported Tools table footnote, inserts Uninstall before Client Setup,
inserts Repository Layout before Security, and updates the License footer.
No expected merge conflict.

Refs: audit findings M6, M8, M9, M11, L2, L3, L6.

Co-authored-by: dtzp555 <dtzp555@gmail.com>

AGENTS.md

@@ -36,7 +36,9 @@ Runtime: Node.js (ESM, `.mjs` throughout). No build step. No bundler. `server.mj
 - `ALIGNMENT.md` — the constitution. Binding for any `server.mjs` change. See ADR 0002.
 - `.github/workflows/alignment.yml` — CI blacklist grep; fails the build on known-hallucinated tokens.
 - `CLAUDE.md` — Claude-Code-specific session instructions + release_kit overlay (Iron Rule 5.5).
-- `docs/adr/` — Architecture Decision Records. Read these before proposing governance or SPOT changes.
+- `docs/adr/` — Architecture Decision Records. Read these before proposing governance or SPOT changes. See `docs/adr/README.md` for the index.
+- `docs/superpowers/plans/` — active spec-kit plans. `docs/superpowers/plans/shipped/` archives plans that have been delivered (don't propose changes against shipped plans — they're history). `docs/superpowers/specs/` holds long-lived design documents that other code references (e.g., the SSE heartbeat design referenced from `server.mjs`).
+- `memory/constitution.md` — spec-kit's project constitution (its standard `memory/` location). Distinct from `~/.cc-rules/memory/` (cross-machine personal memory) and from this repo's `ALIGNMENT.md` (the OCP code-level constitution).
 
 ---
 
@@ -66,7 +68,7 @@ A fresh session picking up OCP work should read, in order:
 2. `ALIGNMENT.md` — constitution; non-optional.
 3. `CLAUDE.md` — tool-specific instructions and release_kit overlay.
 4. `docs/adr/` — most recent ADRs first; they explain why the current structure exists.
-5. Any active spec under `docs/superpowers/specs/*/tasks.md` (if present).
+5. Any active plan under `docs/superpowers/plans/` (excluding `shipped/` which is the archive).
 6. `~/.cc-rules/memory/auto/MEMORY.md` — cross-machine memory index.
 
 Only after these should the session touch code.