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/api/tests/unit/test_home_path_expansion.py

@@ -12,7 +12,9 @@ class TestExpandContainerPath:
 
     def test_tilde_slash_expands(self) -> None:
         """~/foo should expand to home_dir/foo."""
-        assert expand_container_path("~/workspace", "/home/user") == "/home/user/workspace"
+        assert (
+            expand_container_path("~/workspace", "/home/user") == "/home/user/workspace"
+        )
 
     def test_tilde_alone_expands(self) -> None:
         """~ should expand to home_dir."""
@@ -20,7 +22,10 @@ class TestExpandContainerPath:
 
     def test_dollar_home_slash_expands(self) -> None:
         """$HOME/foo should expand to home_dir/foo."""
-        assert expand_container_path("$HOME/workspace", "/home/user") == "/home/user/workspace"
+        assert (
+            expand_container_path("$HOME/workspace", "/home/user")
+            == "/home/user/workspace"
+        )
 
     def test_dollar_home_alone_expands(self) -> None:
         """$HOME should expand to home_dir."""
@@ -78,7 +83,9 @@ class TestResolveGitMountMappingsExpansion:
         """Mapping with ~/repo target expands to home dir."""
         (tmp_path / "src").mkdir()
         mappings = [{"source_path": "src", "target_path": "~/repo"}]
-        result = _resolve_git_mount_mappings(str(tmp_path), mappings, None, "/home/user")
+        result = _resolve_git_mount_mappings(
+            str(tmp_path), mappings, None, "/home/user"
+        )
         assert len(result) == 1
         assert result[0]["target"] == "/home/user/repo"
 
@@ -86,7 +93,9 @@ class TestResolveGitMountMappingsExpansion:
         """Mapping with $HOME/repo target expands to home dir."""
         (tmp_path / "src").mkdir()
         mappings = [{"source_path": "src", "target_path": "$HOME/repo"}]
-        result = _resolve_git_mount_mappings(str(tmp_path), mappings, None, "/home/user")
+        result = _resolve_git_mount_mappings(
+            str(tmp_path), mappings, None, "/home/user"
+        )
         assert len(result) == 1
         assert result[0]["target"] == "/home/user/repo"
 
@@ -94,6 +103,8 @@ class TestResolveGitMountMappingsExpansion:
         """Absolute target paths are not modified."""
         (tmp_path / "src").mkdir()
         mappings = [{"source_path": "src", "target_path": "/app/src"}]
-        result = _resolve_git_mount_mappings(str(tmp_path), mappings, None, "/home/user")
+        result = _resolve_git_mount_mappings(
+            str(tmp_path), mappings, None, "/home/user"
+        )
         assert len(result) == 1
         assert result[0]["target"] == "/app/src"