fix: subagent windows not opening — two cascading bugs

1. handleInit crash: commit cdc822d removed Map initializations for
   teammateTerminals, teammatePanesByName, teams, teamTasks, teammateMap
   from the constructor but left cleanup code that iterates them.
   cleanupAllFloatingWindows() crashed on "not iterable", preventing
   ALL frontend data (sessions, subagents) from loading.

2. claudeSessionId null on recovered sessions: only set inside
   startInteractive(), never in constructor or persisted. After server
   restart, recovered sessions had null claudeSessionId, so the
   hasMatchingTab check always failed → no subagent windows.

Fixes:
- Re-add all 5 missing Map initializations in app.js constructor
- Set _claudeSessionId = this.id in Session constructor (Claudeman
  always passes --session-id to Claude, so they always match)

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

src/web/server.ts

@@ -1524,7 +1524,7 @@ export class WebServer extends EventEmitter {
       // Use writeViaScreen for programmatic input (more reliable for mux sessions)
       let success = false;
       if (useScreen) {
-        success = session.writeViaScreen(inputStr);
+        success = await session.writeViaScreen(inputStr);
         if (!success) {
           console.warn(`[Server] writeViaScreen failed for session ${id}, falling back to direct write`);
           // Fallback to direct write if screen write fails