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

tests/test_shared_write_access.py

@@ -40,8 +40,7 @@ async def test_editor_share_can_update_and_writes_as_the_owner():
     with patch.object(svc, "get_snippet", AsyncMock(return_value=note)), \
          patch("scribe.services.access.can_write_note", AsyncMock(return_value=True)), \
          patch.object(svc.notes_svc, "update_note",
-                      AsyncMock(return_value=updated)) as mock_update, \
-         patch.object(svc, "_embed_snippet", MagicMock()):
+                      AsyncMock(return_value=updated)) as mock_update:
         got = await svc.update_snippet(7, 1, name="formatDuration")
 
     assert got is updated
@@ -107,8 +106,7 @@ async def test_merge_skips_sources_owned_by_someone_else():
     with patch.object(svc, "get_snippet", AsyncMock(side_effect=fake_get)), \
          patch("scribe.services.access.can_write_note", AsyncMock(return_value=True)), \
          patch.object(svc.notes_svc, "update_note", AsyncMock(return_value=target)), \
-         patch("scribe.services.trash.delete", AsyncMock(return_value=object())), \
-         patch.object(svc, "_embed_snippet", MagicMock()):
+         patch("scribe.services.trash.delete", AsyncMock(return_value=object())):
         _note, merged_ids = await svc.merge_snippets(7, 1, [2, 3])
 
     assert merged_ids == [2]