fix: unified fullscreen terminal header

- Add showControls prop to TerminalComponent to optionally hide internal header
- Add reset() method to TerminalRef for external reset control
- TerminalPage now renders a unified fullscreen header bar combining:
  - Session tabs (TerminalSessionTabs)
  - Terminal controls (status dot, A-, A+, Reset, Exit Fullscreen)
- Unified header is always visible in fullscreen (no hover-to-reveal)
- TerminalComponent internal header hidden when in fullscreen mode
- Remove old CSS that hid session tabs with opacity:0 until hover

Quality gates: pytest 188 passed, frontend typecheck clean

Fixes: terminal-fullscreen-unified-header

apps/web/src/styles.css

@@ -2890,18 +2890,57 @@ a.nav-item,
 	border-radius: 0;
 }
 
-.terminal-page.fullscreen .terminal-session-tabs {
-	position: absolute;
-	top: 0;
-	left: 0;
-	right: 0;
-	z-index: 10;
-	opacity: 0;
-	transition: opacity 0.3s;
+/* Unified fullscreen header: session tabs + terminal controls */
+.terminal-fullscreen-header {
+	display: flex;
+	align-items: center;
+	justify-content: space-between;
+	background: #2d2d2d;
+	border-bottom: 1px solid #3e3e3e;
+	flex-shrink: 0;
+	min-height: 0;
 }
 
-.terminal-page.fullscreen .terminal-session-tabs:hover {
-	opacity: 1;
+.terminal-fullscreen-header-tabs {
+	flex: 1;
+	min-width: 0;
+	overflow: hidden;
+}
+
+.terminal-fullscreen-header-tabs .terminal-session-tabs {
+	background: transparent;
+	border-bottom: none;
+}
+
+.terminal-fullscreen-header-controls {
+	display: flex;
+	align-items: center;
+	gap: var(--space-2);
+	padding: 0 var(--space-3);
+	flex-shrink: 0;
+	border-left: 1px solid #3e3e3e;
+}
+
+.terminal-fullscreen-status {
+	width: 8px;
+	height: 8px;
+	border-radius: 50%;
+	background: #666;
+	flex-shrink: 0;
+}
+
+.terminal-fullscreen-status.connecting {
+	background: #f5f543;
+	animation: pulse 1.5s infinite;
+}
+
+.terminal-fullscreen-status.connected {
+	background: #0dbc79;
+}
+
+.terminal-fullscreen-status.disconnected,
+.terminal-fullscreen-status.error {
+	background: #cd3131;
 }
 
 /* Mobile auto-hide header and tabs */