feat(v0.3): H4 — live Claude status badge + notifications + setup-hooks

- terminal-session: handle 'status' frame → claudeStatus + onClaudeStatus
- tabs: per-tab Claude glyph (⚙ working / ⏳ waiting / ✓ idle); inactive
  'waiting' tab gets an amber highlight + a browser notification (permission
  requested on first tab switch)
- scripts/setup-hooks.mjs + 'npm run setup-hooks': idempotently install/remove
  command hooks in ~/.claude/settings.json (inline curl to $WEBTERM_HOOK_URL with
  $WEBTERM_SESSION; no-op outside web-terminal); backs up settings.json
- Browser-verified end-to-end: PermissionRequest→⏳, PreToolUse→⚙, Stop→✓;
  inactive waiting tab shows amber + glyph. 205 tests green.

public/style.css

@@ -202,6 +202,18 @@ html, body {
   font-weight: 600;
 }
 
+/* Claude Code activity glyph (H2/H4) */
+.tab-claude {
+  margin-right: 6px;
+  font-size: 12px;
+  flex: none;
+}
+/* A background tab that needs approval gets an amber outline. */
+.tab.claude-waiting {
+  background-color: #3a2a10;
+  box-shadow: inset 0 -2px 0 #d29922;
+}
+
 /* Drag-to-reorder feedback. */
 .tab.dragging {
   opacity: 0.4;