Skills engine v0.1 + multi-channel infrastructure (#307)

* refactor: multi-channel infrastructure with explicit channel/is_group tracking

- Add channels[] array and findChannel() routing in index.ts, replacing
  hardcoded whatsapp.* calls with channel-agnostic callbacks
- Add channel TEXT and is_group INTEGER columns to chats table with
  COALESCE upsert to protect existing values from null overwrites
- is_group defaults to 0 (safe: unknown chats excluded from groups)
- WhatsApp passes explicit channel='whatsapp' and isGroup to onChatMetadata
- getAvailableGroups filters on is_group instead of JID pattern matching
- findChannel logs warnings instead of silently dropping unroutable JIDs
- Migration backfills channel/is_group from JID patterns for existing DBs

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

* feat: skills engine v0.1 — deterministic skill packages with rerere resolution

Three-way merge engine for applying skill packages on top of a core
codebase. Skills declare which files they add/modify, and the engine
uses git merge-file for conflict detection with git rerere for
automatic resolution of previously-seen conflicts.

Key components:
- apply: three-way merge with backup/rollback safety net
- replay: clean-slate replay for uninstall and rebase
- update: core version updates with deletion detection
- rebase: bake applied skills into base (one-way)
- manifest: validation with path traversal protection
- resolution-cache: pre-computed rerere resolutions
- structured: npm deps, env vars, docker-compose merging
- CI: per-skill test matrix with conflict detection

151 unit tests covering merge, rerere, backup, replay, uninstall,
update, rebase, structured ops, and edge cases.

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

* feat: add Discord and Telegram skill packages

Skill packages for adding Discord and Telegram channels to NanoClaw.
Each package includes:
- Channel implementation (add/src/channels/)
- Three-way merge targets for index.ts, config.ts, routing.test.ts
- Intent docs explaining merge invariants
- Standalone integration tests
- manifest.yaml with dependency/conflict declarations

Applied via: npx tsx scripts/apply-skill.ts .claude/skills/add-discord
These are inert until applied — no runtime impact.

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

* remove unused docs (skills-system-status, implementation-guide)

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

---------

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

src/routing.test.ts

@@ -22,30 +22,26 @@ describe('JID ownership patterns', () => {
     const jid = '12345678@s.whatsapp.net';
     expect(jid.endsWith('@s.whatsapp.net')).toBe(true);
   });
-
-  it('unknown JID format: does not match WhatsApp patterns', () => {
-    const jid = 'unknown:12345';
-    expect(jid.endsWith('@g.us')).toBe(false);
-    expect(jid.endsWith('@s.whatsapp.net')).toBe(false);
-  });
 });
 
 // --- getAvailableGroups ---
 
 describe('getAvailableGroups', () => {
-  it('returns only @g.us JIDs', () => {
-    storeChatMetadata('group1@g.us', '2024-01-01T00:00:01.000Z', 'Group 1');
-    storeChatMetadata('user@s.whatsapp.net', '2024-01-01T00:00:02.000Z', 'User DM');
-    storeChatMetadata('group2@g.us', '2024-01-01T00:00:03.000Z', 'Group 2');
+  it('returns only groups, excludes DMs', () => {
+    storeChatMetadata('group1@g.us', '2024-01-01T00:00:01.000Z', 'Group 1', 'whatsapp', true);
+    storeChatMetadata('user@s.whatsapp.net', '2024-01-01T00:00:02.000Z', 'User DM', 'whatsapp', false);
+    storeChatMetadata('group2@g.us', '2024-01-01T00:00:03.000Z', 'Group 2', 'whatsapp', true);
 
     const groups = getAvailableGroups();
     expect(groups).toHaveLength(2);
-    expect(groups.every((g) => g.jid.endsWith('@g.us'))).toBe(true);
+    expect(groups.map((g) => g.jid)).toContain('group1@g.us');
+    expect(groups.map((g) => g.jid)).toContain('group2@g.us');
+    expect(groups.map((g) => g.jid)).not.toContain('user@s.whatsapp.net');
   });
 
   it('excludes __group_sync__ sentinel', () => {
     storeChatMetadata('__group_sync__', '2024-01-01T00:00:00.000Z');
-    storeChatMetadata('group@g.us', '2024-01-01T00:00:01.000Z', 'Group');
+    storeChatMetadata('group@g.us', '2024-01-01T00:00:01.000Z', 'Group', 'whatsapp', true);
 
     const groups = getAvailableGroups();
     expect(groups).toHaveLength(1);
@@ -53,8 +49,8 @@ describe('getAvailableGroups', () => {
   });
 
   it('marks registered groups correctly', () => {
-    storeChatMetadata('reg@g.us', '2024-01-01T00:00:01.000Z', 'Registered');
-    storeChatMetadata('unreg@g.us', '2024-01-01T00:00:02.000Z', 'Unregistered');
+    storeChatMetadata('reg@g.us', '2024-01-01T00:00:01.000Z', 'Registered', 'whatsapp', true);
+    storeChatMetadata('unreg@g.us', '2024-01-01T00:00:02.000Z', 'Unregistered', 'whatsapp', true);
 
     _setRegisteredGroups({
       'reg@g.us': {
@@ -74,9 +70,9 @@ describe('getAvailableGroups', () => {
   });
 
   it('returns groups ordered by most recent activity', () => {
-    storeChatMetadata('old@g.us', '2024-01-01T00:00:01.000Z', 'Old');
-    storeChatMetadata('new@g.us', '2024-01-01T00:00:05.000Z', 'New');
-    storeChatMetadata('mid@g.us', '2024-01-01T00:00:03.000Z', 'Mid');
+    storeChatMetadata('old@g.us', '2024-01-01T00:00:01.000Z', 'Old', 'whatsapp', true);
+    storeChatMetadata('new@g.us', '2024-01-01T00:00:05.000Z', 'New', 'whatsapp', true);
+    storeChatMetadata('mid@g.us', '2024-01-01T00:00:03.000Z', 'Mid', 'whatsapp', true);
 
     const groups = getAvailableGroups();
     expect(groups[0].jid).toBe('new@g.us');
@@ -84,6 +80,19 @@ describe('getAvailableGroups', () => {
     expect(groups[2].jid).toBe('old@g.us');
   });
 
+  it('excludes non-group chats regardless of JID format', () => {
+    // Unknown JID format stored without is_group should not appear
+    storeChatMetadata('unknown-format-123', '2024-01-01T00:00:01.000Z', 'Unknown');
+    // Explicitly non-group with unusual JID
+    storeChatMetadata('custom:abc', '2024-01-01T00:00:02.000Z', 'Custom DM', 'custom', false);
+    // A real group for contrast
+    storeChatMetadata('group@g.us', '2024-01-01T00:00:03.000Z', 'Group', 'whatsapp', true);
+
+    const groups = getAvailableGroups();
+    expect(groups).toHaveLength(1);
+    expect(groups[0].jid).toBe('group@g.us');
+  });
+
   it('returns empty array when no chats exist', () => {
     const groups = getAvailableGroups();
     expect(groups).toHaveLength(0);