feat: Add indexing group to CodexLens environment variable schema

- Introduced a new `indexing` group in the environment variable schema with fields for AST grep usage, static graph enablement, and relationship types.
- Updated the CodexLens configuration to support new indexing features.

feat: Enhance DashboardToolbar with session and fullscreen controls

- Added props for session sidebar visibility and fullscreen mode to the DashboardToolbar component.
- Implemented handlers for toggling session sidebar and fullscreen mode.
- Updated the toolbar layout to include session sidebar toggle and fullscreen button.

refactor: Improve TerminalGrid and TerminalPane components

- Refactored GridGroupRenderer to handle pane size changes directly via store.
- Enhanced TerminalPane to remove unused file browser logic and improve layout handling.
- Updated key generation for child panes to ensure stability.

feat: Extend CodexLens API for staged Stage-2 expansion modes

- Added support for `staged_stage2_mode` in the CodexLens API, allowing for different expansion strategies.
- Updated semantic search handlers to process new stage-2 mode parameter.
- Implemented validation and handling for new stage-2 modes in the backend.

test: Add benchmarks for staged Stage-2 modes comparison

- Created a benchmark script to compare performance and results of different staged Stage-2 modes.
- Included metrics for latency, overlap, and diversity across modes.

ccw/frontend/src/components/codexlens/SearchTab.tsx

@@ -24,7 +24,12 @@ import {
   useCodexLensLspStatus,
   useCodexLensSemanticSearch,
 } from '@/hooks/useCodexLens';
-import type { CodexLensSearchParams, CodexLensSemanticSearchMode, CodexLensFusionStrategy } from '@/lib/api';
+import type {
+  CodexLensSearchParams,
+  CodexLensSemanticSearchMode,
+  CodexLensFusionStrategy,
+  CodexLensStagedStage2Mode,
+} from '@/lib/api';
 import { cn } from '@/lib/utils';
 
 type SearchType = 'search' | 'search_files' | 'symbol' | 'semantic';
@@ -40,6 +45,7 @@ export function SearchTab({ enabled }: SearchTabProps) {
   const [searchMode, setSearchMode] = useState<SearchMode>('dense_rerank');
   const [semanticMode, setSemanticMode] = useState<CodexLensSemanticSearchMode>('fusion');
   const [fusionStrategy, setFusionStrategy] = useState<CodexLensFusionStrategy>('rrf');
+  const [stagedStage2Mode, setStagedStage2Mode] = useState<CodexLensStagedStage2Mode>('precomputed');
   const [query, setQuery] = useState('');
   const [hasSearched, setHasSearched] = useState(false);
 
@@ -76,6 +82,7 @@ export function SearchTab({ enabled }: SearchTabProps) {
       query,
       mode: semanticMode,
       fusion_strategy: semanticMode === 'fusion' ? fusionStrategy : undefined,
+      staged_stage2_mode: semanticMode === 'fusion' && fusionStrategy === 'staged' ? stagedStage2Mode : undefined,
       limit: 20,
       include_match_reason: true,
     },
@@ -123,6 +130,11 @@ export function SearchTab({ enabled }: SearchTabProps) {
     setHasSearched(false);
   };
 
+  const handleStagedStage2ModeChange = (value: CodexLensStagedStage2Mode) => {
+    setStagedStage2Mode(value);
+    setHasSearched(false);
+  };
+
   const handleQueryChange = (value: string) => {
     setQuery(value);
     setHasSearched(false);
@@ -308,6 +320,29 @@ export function SearchTab({ enabled }: SearchTabProps) {
         </div>
       )}
 
+      {/* Staged Stage-2 Mode - only when semantic + fusion + staged */}
+      {searchType === 'semantic' && semanticMode === 'fusion' && fusionStrategy === 'staged' && (
+        <div className="space-y-2">
+          <Label>{formatMessage({ id: 'codexlens.search.stagedStage2Mode' })}</Label>
+          <Select value={stagedStage2Mode} onValueChange={handleStagedStage2ModeChange}>
+            <SelectTrigger>
+              <SelectValue />
+            </SelectTrigger>
+            <SelectContent>
+              <SelectItem value="precomputed">
+                {formatMessage({ id: 'codexlens.search.stagedStage2Mode.precomputed' })}
+              </SelectItem>
+              <SelectItem value="realtime">
+                {formatMessage({ id: 'codexlens.search.stagedStage2Mode.realtime' })}
+              </SelectItem>
+              <SelectItem value="static_global_graph">
+                {formatMessage({ id: 'codexlens.search.stagedStage2Mode.static_global_graph' })}
+              </SelectItem>
+            </SelectContent>
+          </Select>
+        </div>
+      )}
+
       {/* Query Input */}
       <div className="space-y-2">
         <Label htmlFor="search-query">{formatMessage({ id: 'codexlens.search.query' })}</Label>

ccw/frontend/src/components/codexlens/envVarSchema.ts

@@ -2,7 +2,7 @@
 // CodexLens Environment Variable Schema
 // ========================================
 // TypeScript port of ENV_VAR_GROUPS from codexlens-manager.js
-// Defines the 5 structured groups: embedding, reranker, concurrency, cascade, chunking
+// Defines structured groups for CodexLens configuration
 
 import type { EnvVarGroupsSchema } from '@/types/codexlens';
 
@@ -306,6 +306,36 @@ export const envVarGroupsSchema: EnvVarGroupsSchema = {
       },
     },
   },
+  indexing: {
+    id: 'indexing',
+    labelKey: 'codexlens.envGroup.indexing',
+    icon: 'git-branch',
+    vars: {
+      CODEXLENS_USE_ASTGREP: {
+        key: 'CODEXLENS_USE_ASTGREP',
+        labelKey: 'codexlens.envField.useAstGrep',
+        type: 'checkbox',
+        default: 'false',
+        settingsPath: 'parsing.use_astgrep',
+      },
+      CODEXLENS_STATIC_GRAPH_ENABLED: {
+        key: 'CODEXLENS_STATIC_GRAPH_ENABLED',
+        labelKey: 'codexlens.envField.staticGraphEnabled',
+        type: 'checkbox',
+        default: 'false',
+        settingsPath: 'indexing.static_graph_enabled',
+      },
+      CODEXLENS_STATIC_GRAPH_RELATIONSHIP_TYPES: {
+        key: 'CODEXLENS_STATIC_GRAPH_RELATIONSHIP_TYPES',
+        labelKey: 'codexlens.envField.staticGraphRelationshipTypes',
+        type: 'text',
+        placeholder: 'imports,inherits,calls',
+        default: 'imports,inherits',
+        settingsPath: 'indexing.static_graph_relationship_types',
+        showWhen: (env) => env['CODEXLENS_STATIC_GRAPH_ENABLED'] === 'true',
+      },
+    },
+  },
   chunking: {
     id: 'chunking',
     labelKey: 'codexlens.envGroup.chunking',