feat(skill): add WhatsApp reactions skill (emoji reactions + status tracker) (#509)

* feat(skill): add reactions skill (emoji reactions + status tracker)

* refactor(reactions): minimize overlays per upstream review

Address gavrielc's review on qwibitai/nanoclaw#509:
- SKILL.md: remove all inline code, follow add-telegram/add-whatsapp pattern (465→79 lines)
- Rebuild overlays as minimal deltas against upstream/main base
- ipc-mcp-stdio.ts: upstream base + only react_to_message tool (8% delta)
- ipc.ts: upstream base + only reactions delta (14% delta)
- group-queue.test.ts: upstream base + isActive tests only (5% delta)
- Remove group-queue.ts overlay (isActive provided by container-hardening)
- Remove group-queue.ts from manifest modifies list

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

.claude/skills/add-reactions/manifest.yaml

@@ -0,0 +1,23 @@
+skill: reactions
+version: 1.0.0
+description: "WhatsApp emoji reaction support with status tracking"
+core_version: 0.1.0
+adds:
+  - scripts/migrate-reactions.ts
+  - container/skills/reactions/SKILL.md
+  - src/status-tracker.ts
+  - src/status-tracker.test.ts
+modifies:
+  - src/db.ts
+  - src/db.test.ts
+  - src/channels/whatsapp.ts
+  - src/types.ts
+  - src/ipc.ts
+  - src/index.ts
+  - container/agent-runner/src/ipc-mcp-stdio.ts
+  - src/channels/whatsapp.test.ts
+  - src/group-queue.test.ts
+  - src/ipc-auth.test.ts
+conflicts: []
+depends: []
+test: "npx tsc --noEmit"