Add AI categorization with Ollama: settings, auto-classify on sync/import, and manual classify from Transactions

Adds local LLM-based transaction categorization using Ollama:
- Settings UI to configure Ollama URL, model, confidence threshold
- Auto-categorization during bank sync and file import
- Manual "Classify Uncategorized" button on Transactions screen that respects active filters
- Payee default category learning loop for classified transactions

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

frontend/src/services/aiCategorization.ts

@@ -0,0 +1,16 @@
+import api from './api'
+import type { AiCategorizationSettings, OllamaConnectionTestResult, ClassifyUncategorizedResult } from '@/types'
+
+export const aiCategorizationApi = {
+  getSettings: () =>
+    api.get<AiCategorizationSettings>('/ai-categorization/settings'),
+
+  updateSettings: (data: AiCategorizationSettings) =>
+    api.put<AiCategorizationSettings>('/ai-categorization/settings', data),
+
+  testConnection: () =>
+    api.post<OllamaConnectionTestResult>('/ai-categorization/test-connection'),
+
+  classifyUncategorized: (data: { accountId?: string; startDate?: string; endDate?: string; searchText?: string; status?: string }) =>
+    api.post<ClassifyUncategorizedResult>('/ai-categorization/classify', data),
+}