feat: add AI auto-fix UI — types, API client, ValidationSummary button, review modal, and TreeEditorPage wiring

- New ai-fix.ts types for request/response
- fixTree() method on treesApi
- "Fix with AI" button in ValidationSummary (shows for fixable errors)
- AIFixReviewModal with per-fix apply/skip and apply-all
- TreeEditorPage orchestrates the fix flow

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

frontend/src/types/ai-fix.ts

@@ -0,0 +1,24 @@
+export interface AIFixValidationError {
+  node_id: string
+  message: string
+}
+
+export interface AIFixProposal {
+  target_node_id: string
+  error_message: string
+  description: string
+  original_node: Record<string, unknown>
+  fixed_node: Record<string, unknown>
+}
+
+export interface AIFixTreeRequest {
+  tree_structure: Record<string, unknown>
+  tree_name: string
+  tree_type: 'troubleshooting' | 'procedural' | 'maintenance'
+  validation_errors: AIFixValidationError[]
+}
+
+export interface AIFixTreeResponse {
+  fixes: AIFixProposal[]
+  tokens_used: { input: number; output: number }
+}

frontend/src/types/index.ts

@@ -45,3 +45,10 @@ export type {
   AIAssembleResponse,
   AIWizardPhase,
 } from './ai'
+
+export type {
+  AIFixTreeRequest,
+  AIFixTreeResponse,
+  AIFixProposal,
+  AIFixValidationError,
+} from './ai-fix'