fix(embeddings): embed in the service, so every caller gets it (#2056)

A note or task created through MCP was not semantically searchable until the
next restart's backfill ran. Embedding fired at the five REST route handlers
and nowhere else; the MCP tools call the service directly, so they skipped it.

The shape of this bug is the reason to care: it is invisible on an instance
that redeploys constantly (this one does, per rule 46) and permanent on one
that doesn't. Rule 115 — the product has to stand up for the install that
restarts twice a year, not just for the one that restarts hourly.

Moved to services/notes.embed_note(), called from create_note and update_note,
and deleted from all five routes. Every caller — REST, MCP, recurrence,
snippets — now gets it by construction rather than by remembering.

Two things fall out of having one implementation instead of six:

- It uses note.user_id, the OWNER. The routes were inconsistent: some passed
  the caller's uid, some the owner's. On a shared record the caller's id mints
  a second embedding row that nothing reads.
- services/snippets.py's _embed_snippet existed only because snippets are
  created via MCP and the routes couldn't cover them. Every one of its four
  call sites goes through notes_svc, so the helper and its four calls are gone,
  along with the eight test patches that existed to neutralise it.

RuntimeError (no running loop — unit tests, scripts) and any indexing failure
are both swallowed: a write that succeeded must not be failed by its index.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UaYUaouG9jjhATyuxCKrQs

src/scribe/services/snippets.py

@@ -28,7 +28,6 @@ came from.
 """
 from __future__ import annotations
 
-import asyncio
 import hashlib
 import logging
 import re
@@ -52,25 +51,6 @@ SNIPPET_TAG = "snippet"
 UNSET: object = object()
 
 
-def _embed_snippet(note) -> None:
-    """Fire-and-forget embedding refresh for a snippet.
-
-    A snippet's whole value is *immediate* recall — it must join the semantic /
-    auto-inject pool the moment it's recorded, not wait for the startup backfill.
-    Unlike a plain note (embedded at the REST-route boundary only, so its MCP
-    create path defers to restart-backfill), a snippet is recorded primarily via
-    MCP, so we embed here in the service — covering BOTH the MCP tool and the
-    REST route by construction. Mirrors the route pattern: fire-and-forget,
-    text = title + body. Import lazily so the pure serialize/parse helpers can be
-    imported without pulling in the embedding model.
-    """
-    text = f"{note.title}\n{note.body}".strip() if note.body else (note.title or "")
-    if not text:
-        return
-    from scribe.services.embeddings import upsert_note_embedding
-    asyncio.create_task(upsert_note_embedding(note.id, note.user_id, text))
-
-
 # --- serialize: structured fields -> note (title/body/tags) ------------------
 
 def compose_title(name: str, when_to_use: str = "") -> str:
@@ -640,7 +620,6 @@ async def create_snippet(
             language=language, code=code, locations=locations,
         ),
     )
-    _embed_snippet(note)
     return note
 
 
@@ -801,9 +780,6 @@ async def update_snippet(
     # As the OWNER: update_note is owner-scoped, so a shared editor's own id
     # would find nothing. The write was authorised by can_write_note above.
     updated = await notes_svc.update_note(note.user_id, snippet_id, **fields)
-    if updated is not None:
-        # Title/body changed → refresh the embedding so recall reflects the edit.
-        _embed_snippet(updated)
     return updated
 
 
@@ -1025,7 +1001,6 @@ async def merge_snippets(user_id: int, target_id: int, source_ids: list[int]):
         if batch is not None:
             merged_ids.append(s.id)
 
-    _embed_snippet(updated)
     return updated, merged_ids
 
 
@@ -1134,5 +1109,4 @@ async def unmerge_snippet(user_id: int, survivor_id: int, source_id: int):
     )
     if updated is None:
         return None
-    _embed_snippet(updated)
     return updated, restored