feat: add full-text search across conversations (#482)

* feat: add full-text search across conversations in sidebar

Add a search mode toggle (Projects/Conversations) to the sidebar search bar.
In Conversations mode, search text content across all JSONL session files
with debounced API calls, highlighted snippets, and click-to-navigate results.

* fix: address PR review feedback - session summary tracking, search sequence invalidation, fallback navigation, SSE streaming

- Track session summaries per-session in a Map instead of file-scoped variable
- Increment searchSeqRef when clearing conversation search to invalidate in-flight requests
- Add fallback session navigation when session not loaded in sidebar paging
- Stream search results via SSE for progressive display with progress indicator

* feat(search): add Codex/Gemini search and scroll-to-message navigation

- Search now includes Codex sessions (JSONL from ~/.codex/sessions/) and
  Gemini sessions (in-memory via sessionManager) in addition to Claude
- Search results include provider info and display a provider badge
- Click handler resolves the correct provider instead of hardcoding claude
- Clicking a search result loads all messages and scrolls to the matched
  message with a highlight flash animation

* fix(search): Codex search path matching and scroll reliability

- Fix Codex search scanning all sessions for every project by checking
  session_meta cwd match BEFORE scanning messages (was inflating match
  count and hitting limit before reaching later projects)
- Fix Codex search missing user messages in response_item entries
  (role=user with input_text content parts)
- Fix scroll-to-message being overridden by initial scrollToBottom
  using searchScrollActiveRef to inhibit competing scroll effects
- Fix snippet matching using contiguous substring instead of
  filtered words (which created non-existent phrases)

* feat(search): add Gemini CLI session support for search and history viewing

Gemini CLI sessions stored in ~/.gemini/tmp/<project>/chats/*.json are now
indexed for conversation search and can be loaded for viewing. Previously
only sessions created through the UI (sessionManager) were searchable.

* fix(search): full-word matching and longer highlight flash

- Search now uses word boundaries (\b) instead of substring matching,
  so "hi" no longer matches "this"
- Highlight flash extended to 4s with thicker outline and subtle
  background tint for better visibility

src/components/sidebar/view/subcomponents/SidebarHeader.tsx

@@ -1,7 +1,10 @@
-import { FolderPlus, Plus, RefreshCw, Search, X, PanelLeftClose } from 'lucide-react';
+import { Folder, FolderPlus, MessageSquare, Plus, RefreshCw, Search, X, PanelLeftClose } from 'lucide-react';
 import type { TFunction } from 'i18next';
 import { Button, Input } from '../../../../shared/view/ui';
 import { IS_PLATFORM } from '../../../../constants/config';
+import { cn } from '../../../../lib/utils';
+
+type SearchMode = 'projects' | 'conversations';
 
 type SidebarHeaderProps = {
   isPWA: boolean;
@@ -11,6 +14,8 @@ type SidebarHeaderProps = {
   searchFilter: string;
   onSearchFilterChange: (value: string) => void;
   onClearSearchFilter: () => void;
+  searchMode: SearchMode;
+  onSearchModeChange: (mode: SearchMode) => void;
   onRefresh: () => void;
   isRefreshing: boolean;
   onCreateProject: () => void;
@@ -26,6 +31,8 @@ export default function SidebarHeader({
   searchFilter,
   onSearchFilterChange,
   onClearSearchFilter,
+  searchMode,
+  onSearchModeChange,
   onRefresh,
   isRefreshing,
   onCreateProject,
@@ -101,23 +108,55 @@ export default function SidebarHeader({
 
         {/* Search bar */}
         {projectsCount > 0 && !isLoading && (
-          <div className="relative mt-2.5">
-            <Search className="pointer-events-none absolute left-3 top-1/2 h-3.5 w-3.5 -translate-y-1/2 text-muted-foreground/50" />
-            <Input
-              type="text"
-              placeholder={t('projects.searchPlaceholder')}
-              value={searchFilter}
-              onChange={(event) => onSearchFilterChange(event.target.value)}
-              className="nav-search-input h-9 rounded-xl border-0 pl-9 pr-8 text-sm transition-all duration-200 placeholder:text-muted-foreground/40 focus-visible:ring-0 focus-visible:ring-offset-0"
-            />
-            {searchFilter && (
+          <div className="mt-2.5 space-y-2">
+            {/* Search mode toggle */}
+            <div className="flex rounded-lg bg-muted/50 p-0.5">
               <button
-                onClick={onClearSearchFilter}
-                className="absolute right-2.5 top-1/2 -translate-y-1/2 rounded-md p-0.5 hover:bg-accent"
+                onClick={() => onSearchModeChange('projects')}
+                aria-pressed={searchMode === 'projects'}
+                className={cn(
+                  "flex-1 flex items-center justify-center gap-1.5 rounded-md px-2 py-1.5 text-xs font-medium transition-all",
+                  searchMode === 'projects'
+                    ? "bg-background shadow-sm text-foreground"
+                    : "text-muted-foreground hover:text-foreground"
+                )}
               >
-                <X className="h-3 w-3 text-muted-foreground" />
+                <Folder className="w-3 h-3" />
+                {t('search.modeProjects')}
               </button>
-            )}
+              <button
+                onClick={() => onSearchModeChange('conversations')}
+                aria-pressed={searchMode === 'conversations'}
+                className={cn(
+                  "flex-1 flex items-center justify-center gap-1.5 rounded-md px-2 py-1.5 text-xs font-medium transition-all",
+                  searchMode === 'conversations'
+                    ? "bg-background shadow-sm text-foreground"
+                    : "text-muted-foreground hover:text-foreground"
+                )}
+              >
+                <MessageSquare className="w-3 h-3" />
+                {t('search.modeConversations')}
+              </button>
+            </div>
+            <div className="relative">
+              <Search className="absolute left-3 top-1/2 -translate-y-1/2 w-3.5 h-3.5 text-muted-foreground/50 pointer-events-none" />
+              <Input
+                type="text"
+                placeholder={searchMode === 'conversations' ? t('search.conversationsPlaceholder') : t('projects.searchPlaceholder')}
+                value={searchFilter}
+                onChange={(event) => onSearchFilterChange(event.target.value)}
+                className="nav-search-input pl-9 pr-8 h-9 text-sm rounded-xl border-0 placeholder:text-muted-foreground/40 focus-visible:ring-0 focus-visible:ring-offset-0 transition-all duration-200"
+              />
+              {searchFilter && (
+                <button
+                  onClick={onClearSearchFilter}
+                  aria-label={t('tooltips.clearSearch')}
+                  className="absolute right-2.5 top-1/2 -translate-y-1/2 p-0.5 hover:bg-accent rounded-md"
+                >
+                  <X className="w-3 h-3 text-muted-foreground" />
+                </button>
+              )}
+            </div>
           </div>
         )}
       </div>
@@ -162,23 +201,54 @@ export default function SidebarHeader({
 
         {/* Mobile search */}
         {projectsCount > 0 && !isLoading && (
-          <div className="relative mt-2.5">
-            <Search className="pointer-events-none absolute left-3 top-1/2 h-4 w-4 -translate-y-1/2 text-muted-foreground/50" />
-            <Input
-              type="text"
-              placeholder={t('projects.searchPlaceholder')}
-              value={searchFilter}
-              onChange={(event) => onSearchFilterChange(event.target.value)}
-              className="nav-search-input h-10 rounded-xl border-0 pl-10 pr-9 text-sm transition-all duration-200 placeholder:text-muted-foreground/40 focus-visible:ring-0 focus-visible:ring-offset-0"
-            />
-            {searchFilter && (
+          <div className="mt-2.5 space-y-2">
+            <div className="flex rounded-lg bg-muted/50 p-0.5">
               <button
-                onClick={onClearSearchFilter}
-                className="absolute right-2.5 top-1/2 -translate-y-1/2 rounded-md p-1 hover:bg-accent"
+                onClick={() => onSearchModeChange('projects')}
+                aria-pressed={searchMode === 'projects'}
+                className={cn(
+                  "flex-1 flex items-center justify-center gap-1.5 rounded-md px-2 py-1.5 text-xs font-medium transition-all",
+                  searchMode === 'projects'
+                    ? "bg-background shadow-sm text-foreground"
+                    : "text-muted-foreground hover:text-foreground"
+                )}
               >
-                <X className="h-3.5 w-3.5 text-muted-foreground" />
+                <Folder className="w-3 h-3" />
+                {t('search.modeProjects')}
               </button>
-            )}
+              <button
+                onClick={() => onSearchModeChange('conversations')}
+                aria-pressed={searchMode === 'conversations'}
+                className={cn(
+                  "flex-1 flex items-center justify-center gap-1.5 rounded-md px-2 py-1.5 text-xs font-medium transition-all",
+                  searchMode === 'conversations'
+                    ? "bg-background shadow-sm text-foreground"
+                    : "text-muted-foreground hover:text-foreground"
+                )}
+              >
+                <MessageSquare className="w-3 h-3" />
+                {t('search.modeConversations')}
+              </button>
+            </div>
+            <div className="relative">
+              <Search className="absolute left-3 top-1/2 -translate-y-1/2 w-4 h-4 text-muted-foreground/50 pointer-events-none" />
+              <Input
+                type="text"
+                placeholder={searchMode === 'conversations' ? t('search.conversationsPlaceholder') : t('projects.searchPlaceholder')}
+                value={searchFilter}
+                onChange={(event) => onSearchFilterChange(event.target.value)}
+                className="nav-search-input pl-10 pr-9 h-10 text-sm rounded-xl border-0 placeholder:text-muted-foreground/40 focus-visible:ring-0 focus-visible:ring-offset-0 transition-all duration-200"
+              />
+              {searchFilter && (
+                <button
+                  onClick={onClearSearchFilter}
+                  aria-label={t('tooltips.clearSearch')}
+                  className="absolute right-2.5 top-1/2 -translate-y-1/2 p-1 hover:bg-accent rounded-md"
+                >
+                  <X className="w-3.5 h-3.5 text-muted-foreground" />
+                </button>
+              )}
+            </div>
           </div>
         )}
       </div>