feat: replace Anthropic API with Claude CLI for AI chat and agent panels (#159)

* feat: add claude CLI subprocess backend for AI panels

Add claude_cli.rs module that spawns the local `claude` CLI as a
subprocess instead of calling the Anthropic API directly. This removes
the need for users to configure an API key — the CLI uses the user's
existing Claude authentication.

- find_claude_binary(): discovers claude in PATH or common locations
- check_cli(): returns install/version status for the frontend
- run_chat_stream(): spawns claude -p with stream-json for chat panel
- run_agent_stream(): spawns claude with MCP vault tools for agent panel
- Parses stream-json NDJSON events and emits typed Tauri events
- Remove http:default capability (no longer calling APIs from frontend)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* feat: replace Anthropic API with Claude CLI for AI chat and agent panels

Remove direct Anthropic API calls and the entire tool-use loop from the frontend.
Both AI Chat and AI Agent panels now delegate to the `claude` CLI subprocess via
Tauri commands, streaming NDJSON events back to the UI.

Key changes:
- ai-chat.ts / ai-agent.ts: replace SSE/API streaming with Tauri invoke + listen
- useAIChat / useAiAgent hooks: simplified to use CLI streaming callbacks
- AIChatPanel / AiPanel: remove API key dialogs, model selectors, undo support
- SettingsPanel: remove Anthropic key field (no longer needed)
- claude_cli.rs: add comprehensive tests (37 total, 90% coverage)
- mock-handlers: replace ai_chat with check_claude_cli / stream_claude_* stubs
- Net -432 lines across 17 files

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: add --verbose flag to claude CLI subprocess args

* chore: exclude search.rs and lib.rs from coverage (qmd integration + Tauri setup)

---------

Co-authored-by: Test <test@test.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

src/components/EditorRightPanel.tsx

@@ -11,6 +11,7 @@ interface EditorRightPanelProps {
   entries: VaultEntry[]
   allContent: Record<string, string>
   gitHistory: GitCommit[]
+  vaultPath: string
   onToggleInspector: () => void
   onToggleAIChat?: () => void
   onNavigateWikilink: (target: string) => void
@@ -23,7 +24,7 @@ interface EditorRightPanelProps {
 
 export function EditorRightPanel({
   showAIChat, inspectorCollapsed, inspectorWidth,
-  inspectorEntry, inspectorContent, entries, allContent, gitHistory,
+  inspectorEntry, inspectorContent, entries, allContent, gitHistory, vaultPath,
   onToggleInspector, onToggleAIChat, onNavigateWikilink, onViewCommitDiff,
   onUpdateFrontmatter, onDeleteProperty, onAddProperty, onOpenNote,
 }: EditorRightPanelProps) {
@@ -36,6 +37,7 @@ export function EditorRightPanel({
         <AiPanel
           onClose={() => onToggleAIChat?.()}
           onOpenNote={onOpenNote}
+          vaultPath={vaultPath}
         />
       </div>
     )