feat: add host-driven GitHub Actions CI watcher (Level 3)

Replace LLM-per-tick polling with direct `gh api` calls for GitHub
Actions watchers. New `ci_provider` discriminator column routes tasks
to either the host-driven path (zero LLM tokens) or the existing
generic LLM path. GitHub watchers poll at 15s intervals (min 10s)
via `checkGitHubActionsRun()` in the scheduler, with completion
messages sent directly to chat on terminal state.

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

src/ipc.ts

@@ -286,6 +286,8 @@ export async function processTaskIpc(
     schedule_type?: string;
     schedule_value?: string;
     context_mode?: string;
+    ci_provider?: 'github';
+    ci_metadata?: string;
     groupFolder?: string;
     chatJid?: string;
     targetJid?: string;
@@ -404,6 +406,8 @@ export async function processTaskIpc(
           group_folder: targetFolder,
           chat_jid: resolvedTargetJid,
           agent_type: targetGroupEntry.agentType || SERVICE_AGENT_TYPE,
+          ci_provider: data.ci_provider ?? null,
+          ci_metadata: data.ci_metadata ?? null,
           max_duration_ms: isWatchCiTask({ prompt: data.prompt })
             ? DEFAULT_WATCH_CI_MAX_DURATION_MS
             : null,