feat: workspaces, agentic action tools, local Whisper STT, vec recall

- Projects/workspaces: documents grouped into projects; chat RAG scopes to the
  active project. Switcher in the Documents page.
- Agentic action tools: web_search, fetch_url, and remember (first write tool),
  allowlist-gated per playbook.
- Local Whisper STT (faster-whisper, no torch): on-device dictation replacing
  the browser Web Speech API. POST /stt + GET /stt/status; browser fallback.
- Vector index extended to conversation recall (message_vectors), with the
  brute-force cosine scan kept as the fallback.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

synapse/main.py

@@ -290,6 +290,7 @@ async def chat_stream_endpoint(payload: Dict[str, Any]):
             message, get_ollama_manager().embed,
             limit=app_settings.get("rag_top_k", 3),
             min_score=app_settings.get("rag_min_score", 0.6),
+            project_id=app_settings.get("active_project", "") or None,
         )
         doc_titles: list = []
         if doc_hits:
@@ -943,12 +944,70 @@ async def delete_playbook_endpoint(id: UUID):
         raise HTTPException(status_code=500, detail=str(e))
 
 
+# -------------------------
+# Speech-to-text (local Whisper)
+# -------------------------
+from . import stt as _stt
+
+
+@app.get("/stt/status")
+async def stt_status():
+    return {"available": _stt.available()}
+
+
+@app.post("/stt")
+async def stt_transcribe(payload: Dict[str, Any] = Body(...)):
+    if not _stt.available():
+        raise HTTPException(status_code=503, detail="local STT (faster-whisper) not installed")
+    audio = payload.get("audio") or ""
+    if not audio:
+        raise HTTPException(status_code=400, detail="audio (base64) is required")
+    try:
+        text = await _asyncio.to_thread(_stt.transcribe_b64, audio)
+    except Exception as e:
+        raise HTTPException(status_code=500, detail=f"transcription failed: {e}")
+    return {"text": text}
+
+
+# -------------------------
+# Projects / workspaces
+# -------------------------
+def _active_project() -> str:
+    """The active project id, or '' for the unscoped 'All' view."""
+    return store.get_settings().get("active_project", "") or ""
+
+
+@app.get("/projects")
+async def list_projects():
+    return {"projects": store.list_projects(), "active": _active_project()}
+
+
+@app.post("/projects")
+async def create_project(payload: Dict[str, Any] = Body(...)):
+    name = (payload.get("name") or "").strip()
+    if not name:
+        raise HTTPException(status_code=400, detail="name is required")
+    return store.create_project(name)
+
+
+@app.delete("/projects/{project_id}")
+async def delete_project(project_id: str):
+    if not store.delete_project(project_id):
+        raise HTTPException(status_code=404, detail="Not Found")
+    # If the deleted project was active, fall back to the "All" view.
+    if _active_project() == project_id:
+        store.update_settings({"active_project": ""})
+    return {"status": "deleted"}
+
+
 # -------------------------
 # Documents (RAG)
 # -------------------------
 @app.get("/documents")
 async def list_documents():
-    return {"documents": store.list_documents()}
+    # Scope to the active project; "" (All) lists everything.
+    active = _active_project()
+    return {"documents": store.list_documents(active if active else None)}
 
 
 @app.post("/documents")
@@ -957,7 +1016,7 @@ async def add_document(payload: Dict[str, Any] = Body(...)):
     content = (payload.get("content") or "").strip()
     if not title or not content:
         raise HTTPException(status_code=400, detail="title and content are required")
-    result = await store.add_document(title, content, get_ollama_manager().embed)
+    result = await store.add_document(title, content, get_ollama_manager().embed, _active_project())
     if result["chunks"] == 0:
         raise HTTPException(status_code=400, detail="no text to index")
     return result
@@ -1000,7 +1059,7 @@ async def upload_document(payload: Dict[str, Any] = Body(...)):
     if not text:
         raise HTTPException(status_code=400, detail="no extractable text in file")
     title = _os.path.splitext(_os.path.basename(filename))[0] or filename
-    return await store.add_document(title, text, get_ollama_manager().embed)
+    return await store.add_document(title, text, get_ollama_manager().embed, _active_project())
 
 
 @app.get("/documents/{doc_id}")