feat(kb): admin CRUD for topics

Backs the Phase 4 topic-management table in the KnowledgeBase EspoCRM
extension ("ניהול" tab → "נושאים" panel). Four new admin endpoints:

  GET    /admin/kb/topics         — list ALL topics including
                                    is_active=false ones, with
                                    source_count joined from kb_source
  POST   /admin/kb/topics         — create. Validates slug shape
                                    (^[a-z][a-z0-9-]{1,62}$) and
                                    uniqueness — clean 400 on duplicate
                                    rather than leaking UniqueViolation
  PUT    /admin/kb/topics/{id}    — patch name, description,
                                    system_prompt_addendum, is_active.
                                    slug is intentionally NOT editable —
                                    the S3 layout depends on it
                                    (inbox/<topic_slug>/<kind>/...)
  DELETE /admin/kb/topics/{id}    — hard-delete; refuses with 409 if
                                    any sources still belong to the
                                    topic. Soft-delete (is_active=false)
                                    is the normal "remove from dropdown"
                                    path

Refs Task Master #15 (espocrm-extensions/KnowledgeBase)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

api/routes/admin_kb.py

@@ -387,3 +387,65 @@ async def reingest_admin_source(request: Request, source_id: int):
 
     asyncio.create_task(kb_admin_sources.process_reingest_job(job_id))
     return {"job_id": job_id, "status": "queued", "source_id": source_id}
+
+
+# ── Phase 4: topic CRUD (Task #15) ─────────────────────────────────────────
+
+class TopicCreate(BaseModel):
+    slug: str = Field(..., min_length=2, max_length=63)
+    name: str = Field(..., min_length=1, max_length=200)
+    description: str | None = Field(None, max_length=1000)
+    system_prompt_addendum: str | None = Field(None, max_length=4000)
+    is_active: bool = True
+
+
+class TopicUpdate(BaseModel):
+    name: str | None = Field(None, max_length=200)
+    description: str | None = Field(None, max_length=1000)
+    system_prompt_addendum: str | None = Field(None, max_length=4000)
+    is_active: bool | None = None
+
+
+@router.get("/topics")
+async def list_admin_topics(request: Request):
+    _verify_admin(request)
+    items = await kb_topics.list_topics_admin()
+    return {"items": items, "count": len(items)}
+
+
+@router.post("/topics")
+async def create_admin_topic(request: Request, body: TopicCreate):
+    _verify_admin(request)
+    try:
+        return await kb_topics.create_topic(
+            slug=body.slug,
+            name=body.name,
+            description=body.description,
+            system_prompt_addendum=body.system_prompt_addendum,
+            is_active=body.is_active,
+        )
+    except ValueError as e:
+        raise HTTPException(status_code=400, detail=str(e))
+
+
+@router.put("/topics/{topic_id}")
+async def update_admin_topic(request: Request, topic_id: int, body: TopicUpdate):
+    _verify_admin(request)
+    fields = body.model_dump(exclude_unset=True)
+    try:
+        return await kb_topics.update_topic(topic_id, fields)
+    except LookupError:
+        raise HTTPException(status_code=404, detail="Topic not found")
+    except ValueError as e:
+        raise HTTPException(status_code=400, detail=str(e))
+
+
+@router.delete("/topics/{topic_id}")
+async def delete_admin_topic(request: Request, topic_id: int):
+    _verify_admin(request)
+    try:
+        return await kb_topics.delete_topic(topic_id)
+    except LookupError:
+        raise HTTPException(status_code=404, detail="Topic not found")
+    except kb_topics.ConflictError as e:
+        raise HTTPException(status_code=409, detail=str(e))