feat(gateway): CommandRegistryService + CommandExecutorService (P8-010) (#178)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

docs/scratchpads/p8-010-command-registry.md

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+# P8-010 Scratchpad — Gateway Phase 2: CommandRegistryService + CommandExecutorService
+
+## Objective
+
+Implement gateway-side command registry system:
+
+- `CommandRegistryService` — owns canonical command manifest, broadcasts on connect
+- `CommandExecutorService` — routes `command:execute` socket events
+- `CommandsModule` — NestJS wiring
+- Wire into `ChatGateway` and `AppModule`
+- Register core commands
+- Tests for CommandRegistryService
+
+## Key Findings from Codebase
+
+### CommandDef shape (from packages/types/src/commands/index.ts)
+
+- `scope: 'core' | 'agent' | 'skill' | 'plugin' | 'admin'` (NOT `category`)
+- `args?: CommandArgDef[]` — array of arg defs, each with `name`, `type`, `optional`, `values?`, `description?`
+- No `aliases` required (it's listed but optional-ish... wait, it IS in the interface)
+- `aliases: string[]` — IS present
+
+### SlashCommandResultPayload requires `conversationId`
+
+- The task spec shows `{ command, success, error }` without `conversationId` but actual type requires it
+- Must include `conversationId` in all return values
+
+### CommandManifest has `skills: SkillCommandDef[]`
+
+- Must include `skills` array in manifest
+
+### userId extraction in ChatGateway
+
+- `client.data.user` holds the user object (set in `handleConnection`)
+- `client.data.user.id` or similar for userId
+
+### AgentModule not imported in ChatModule
+
+- ChatGateway imports AgentService via DI
+- ChatModule doesn't declare imports — AgentModule must be global or imported
+
+### Worktree branch
+
+- Branch: `feat/p8-010-command-registry`
+- Working in: `/home/jwoltje/src/mosaic-mono-v1/.claude/worktrees/agent-ac85b3b2`
+
+## Plan
+
+1. Create `apps/gateway/src/commands/command-registry.service.ts`
+2. Create `apps/gateway/src/commands/command-executor.service.ts`
+3. Create `apps/gateway/src/commands/commands.module.ts`
+4. Modify `apps/gateway/src/app.module.ts` — add CommandsModule
+5. Modify `apps/gateway/src/chat/chat.module.ts` — import CommandsModule
+6. Modify `apps/gateway/src/chat/chat.gateway.ts` — inject services, add handler, emit manifest
+7. Create `apps/gateway/src/commands/command-registry.service.spec.ts`
+
+## Progress
+
+- [ ] Create CommandRegistryService
+- [ ] Create CommandExecutorService
+- [ ] Create CommandsModule
+- [ ] Update AppModule
+- [ ] Update ChatModule
+- [ ] Update ChatGateway
+- [ ] Write tests
+- [ ] Run quality gates
+- [ ] Commit + push + PR
+
+## Risks
+
+- CommandDef `args` shape mismatch from task spec — must use actual type
+- `SlashCommandResultPayload.conversationId` is required — handle missing conversationId