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/public/styles.css

@@ -1673,22 +1673,16 @@ body {
   contain: strict;
   will-change: contents;
 }
-
-/* Tab switch feedback: green glow emerging from black */
-.tab-switch-glow {
+/* Tab switch: green-tinted overlay fades in over old content, fades out to reveal new.
+   Animated via Web Animations API (not CSS keyframes) for reliable GPU compositing.
+   Green glow is visible against the dark terminal — black-on-black was imperceptible. */
+.tab-switch-fade {
   position: absolute;
   inset: 0;
   pointer-events: none;
   z-index: 100;
-  background: radial-gradient(ellipse at center, rgba(34, 197, 94, 0.12) 0%, transparent 70%);
+  background: radial-gradient(ellipse at center, rgba(20, 80, 40, 0.85) 0%, rgba(0, 5, 2, 0.97) 75%);
   box-shadow: inset 0 0 150px 60px rgba(34, 197, 94, 0.35);
-  animation: tab-switch-glow 0.7s ease-out forwards;
-}
-
-@keyframes tab-switch-glow {
-  0%   { opacity: 0; }
-  15%  { opacity: 1; }
-  100% { opacity: 0; }
 }
 
 .terminal-container .xterm {