MAESTRO: fix(hooks): add session-complete handler to enable orphan reaper cleanup

Cherry-picked from PR #844 by @thusdigital. Sessions stayed in active
sessions map forever after summarize, causing the orphan reaper to think
all processes were still active. Adds session-complete as Stop phase 2
hook that calls POST /api/sessions/complete to remove sessions from the
active map, allowing the reaper to correctly identify and clean up
orphaned worker processes. Fixes #842.

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

src/services/worker-service.ts

@@ -908,7 +908,7 @@ async function main() {
       if (!platform || !event) {
         console.error('Usage: claude-mem hook <platform> <event>');
         console.error('Platforms: claude-code, cursor, raw');
-        console.error('Events: context, session-init, observation, summarize');
+        console.error('Events: context, session-init, observation, summarize, session-complete');
         process.exit(1);
       }