feat: add knowledge version history (closes #75, closes #76)

- Added EntryVersion model with author relation
- Implemented automatic versioning on entry create/update
- Added API endpoints for version history:
  - GET /api/knowledge/entries/:slug/versions - list versions
  - GET /api/knowledge/entries/:slug/versions/:version - get specific
  - POST /api/knowledge/entries/:slug/restore/:version - restore version
- Created VersionHistory.tsx component with timeline view
- Added History tab to entry detail page
- Supports version viewing and restoring
- Includes comprehensive tests for version operations
- All TypeScript types are explicit and type-safe

apps/web/src/lib/api/knowledge.ts

@@ -3,7 +3,12 @@
  * Handles knowledge entry-related API requests
  */
 
-import type { KnowledgeEntryWithTags, KnowledgeTag } from "@mosaic/shared";
+import type {
+  KnowledgeEntryWithTags,
+  KnowledgeTag,
+  KnowledgeEntryVersionWithAuthor,
+  PaginatedResponse,
+} from "@mosaic/shared";
 import { EntryStatus, Visibility } from "@mosaic/shared";
 import { apiGet, apiPost, apiPatch, apiDelete, type ApiResponse } from "./client";
 
@@ -44,6 +49,11 @@ export interface UpdateEntryData {
   status?: EntryStatus;
   visibility?: Visibility;
   tags?: string[];
+  changeNote?: string;
+}
+
+export interface RestoreVersionData {
+  changeNote?: string;
 }
 
 /**
@@ -128,6 +138,49 @@ export async function fetchTags(): Promise<KnowledgeTag[]> {
   return response.data;
 }
 
+/**
+ * Fetch version history for an entry
+ */
+export async function fetchVersions(
+  slug: string,
+  page: number = 1,
+  limit: number = 20
+): Promise<PaginatedResponse<KnowledgeEntryVersionWithAuthor>> {
+  const params = new URLSearchParams();
+  params.append("page", page.toString());
+  params.append("limit", limit.toString());
+
+  return apiGet<PaginatedResponse<KnowledgeEntryVersionWithAuthor>>(
+    `/api/knowledge/entries/${slug}/versions?${params.toString()}`
+  );
+}
+
+/**
+ * Fetch a specific version of an entry
+ */
+export async function fetchVersion(
+  slug: string,
+  version: number
+): Promise<KnowledgeEntryVersionWithAuthor> {
+  return apiGet<KnowledgeEntryVersionWithAuthor>(
+    `/api/knowledge/entries/${slug}/versions/${version}`
+  );
+}
+
+/**
+ * Restore a previous version of an entry
+ */
+export async function restoreVersion(
+  slug: string,
+  version: number,
+  data?: RestoreVersionData
+): Promise<KnowledgeEntryWithTags> {
+  return apiPost<KnowledgeEntryWithTags>(
+    `/api/knowledge/entries/${slug}/restore/${version}`,
+    data || {}
+  );
+}
+
 /**
  * Mock entries for development (until backend endpoints are ready)
  */