feat: unified error handling + AI service modularisation

Error handling (Prompt 2):
- src/services/errors.ts: AppError class, normalizeError(), throwServiceError() helper
- 6 services wrapped with try/catch (property, match, need, shortlist, futureSignal, inquiry)
- inquiryService aligned from custom ServiceResult<T> to standard ServiceResponse types
- Results, MatchCenter, FutureAvailability pages show <ErrorState onRetry> on query failure

AI modularisation (Prompt 3):
- src/services/aiService.ts reduced from 755 → 19 lines (barrel re-export)
- src/services/ai/IAIService.ts: typed interface + all response types
- src/services/ai/mock/: needParser, compareBuilder, decisionBrief, listingParser, MockAIService
- src/services/ai/openrouter/OpenRouterAIService.ts: model-agnostic skeleton
- src/services/ai/prompts/: 4 prompt template files (needParsing, matchExplanation, compareSummary, decisionBrief)
- src/services/ai/index.ts: factory selects Mock or OpenRouter via VITE_USE_REAL_AI flag
- All existing import paths unchanged — zero call-site modifications

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

src/services/inquiryService.ts

@@ -1,6 +1,8 @@
 import { MockupInquiryProvider } from '../provider/MockupInquiryProvider'
 import type { InquiryFilters } from '../provider/IInquiryProvider'
 import type { Inquiry, Attachment } from '../domain/inquiry'
+import type { ListResponse, ItemResponse } from './types'
+import { throwServiceError } from './errors'
 
 const provider = MockupInquiryProvider
 
@@ -10,31 +12,29 @@ export interface InquiryReplyPayload {
   attachments?: Attachment[]
 }
 
-type ServiceResult<T> = { data: T; error: null } | { data: null; error: string }
-
 export const inquiryService = {
-  async getActiveInquiries(filters?: InquiryFilters): Promise<ServiceResult<Inquiry[]>> {
+  async getActiveInquiries(filters?: InquiryFilters): Promise<ListResponse<Inquiry>> {
     try {
       const data = await provider.getAll(filters)
-      return { data, error: null }
-    } catch (e) {
-      return { data: null, error: e instanceof Error ? e.message : 'Unbekannter Fehler' }
+      return { data, meta: { total: data.length, page: 1, pageSize: data.length, hasMore: false } }
+    } catch (err) {
+      throwServiceError(err)
     }
   },
 
-  async getInquiryById(id: string): Promise<ServiceResult<Inquiry | null>> {
+  async getInquiryById(id: string): Promise<ItemResponse<Inquiry | null>> {
     try {
       const data = await provider.getById(id)
-      return { data, error: null }
-    } catch (e) {
-      return { data: null, error: e instanceof Error ? e.message : 'Unbekannter Fehler' }
+      return { data }
+    } catch (err) {
+      throwServiceError(err)
     }
   },
 
   async sendInquiryReply(
     inquiryId: string,
     payload: InquiryReplyPayload,
-  ): Promise<ServiceResult<Inquiry>> {
+  ): Promise<ItemResponse<Inquiry>> {
     try {
       const data = await provider.addMessage(inquiryId, {
         senderType: 'supply_user',
@@ -43,27 +43,27 @@ export const inquiryService = {
         body: payload.body,
         attachments: payload.attachments ?? [],
       })
-      return { data, error: null }
-    } catch (e) {
-      return { data: null, error: e instanceof Error ? e.message : 'Unbekannter Fehler' }
+      return { data }
+    } catch (err) {
+      throwServiceError(err)
     }
   },
 
-  async markThreadAsRead(id: string): Promise<ServiceResult<Inquiry>> {
+  async markThreadAsRead(id: string): Promise<ItemResponse<Inquiry>> {
     try {
       const data = await provider.markThreadAsRead(id)
-      return { data, error: null }
-    } catch (e) {
-      return { data: null, error: e instanceof Error ? e.message : 'Unbekannter Fehler' }
+      return { data }
+    } catch (err) {
+      throwServiceError(err)
     }
   },
 
-  async getUnreadCount(): Promise<ServiceResult<number>> {
+  async getUnreadCount(): Promise<ItemResponse<number>> {
     try {
       const data = await provider.getUnreadCount()
-      return { data, error: null }
-    } catch (e) {
-      return { data: null, error: e instanceof Error ? e.message : 'Unbekannter Fehler' }
+      return { data }
+    } catch (err) {
+      throwServiceError(err)
     }
   },
 }