fix(post-merge): clean up stale da verbs introduced via #174 merge

Four call sites where #174 (branched from main before the agnes rename
fully landed in some files) emitted or referenced `da fetch`. None are
operator-visible runtime crashes — but `extractor.py` logs a stale
verb to the operator log and `DATA_SOURCES.md` is current docs:

- connectors/bigquery/extractor.py:431,434 (operator-facing log line on
  unverified BQ entity_type — was suggesting `da fetch`).
- docs/DATA_SOURCES.md:77,85 (current public docs, two refs to
  `da fetch` in the workflow + the BQ scope description).
- tests/test_cli_query_render.py:7 (module docstring listed
  `da fetch / agnes schema / etc.` — now `agnes snapshot create / agnes
  schema / etc.`).
- tests/test_cli_snapshot_create.py:1 (docstring referenced `(folded
  from `da fetch`)` — historical, removed; no value once the rename
  landed).

Pre-existing stale `da` references elsewhere in the branch (templates,
operator runbooks, internal comments) are not touched by this commit —
they live outside the merge surface and are a separate cleanup task.

Verified: 10/10 across the affected test files pass.

connectors/bigquery/extractor.py

@@ -428,11 +428,11 @@ def _init_extract_locked(
                     # Unverified entity type. Skip both the wrap view and
                     # the _meta row. The registry row remains; /api/v2/scan
                     # can still operate from it (builds BQ SQL from
-                    # bucket+source_table), and `da fetch` works.
+                    # bucket+source_table), and `agnes snapshot create` works.
                     logger.warning(
                         "Unverified BQ entity_type %r for %s.%s.%s — master view skipped. "
-                        "Use `da fetch` for this row, or file an issue with a repro to "
-                        "request native support.",
+                        "Use `agnes snapshot create` for this row, or file an issue with "
+                        "a repro to request native support.",
                         entity_type, project_id, dataset, source_table,
                     )
                     continue  # Do NOT insert _meta — no inner view to point at.

docs/DATA_SOURCES.md

@@ -74,7 +74,7 @@ bigquery:
 
 Registers BigQuery tables and views as remote DuckDB views (no data download). Queries
 issued through the master `analytics.duckdb` are forwarded to BigQuery via the DuckDB
-BigQuery extension. See also `da fetch` for the analytical workflow that materializes
+BigQuery extension. See also `agnes snapshot create` for the analytical workflow that materializes
 filtered subsets locally.
 
 ### Requirements
@@ -82,7 +82,7 @@ filtered subsets locally.
 - DuckDB BigQuery extension (auto-installed by the extractor on first run).
 - A GCP service account with `bigquery.metadata.get` on the dataset and
   `bigquery.data.viewer` (or finer) on the table; `bigquery.jobs.create` on the
-  billing project for views and `da fetch` queries.
+  billing project for views and `agnes snapshot create` queries.
 - Credentials resolution: GCE metadata server first, then Application Default
   Credentials (`gcloud auth application-default login` or
   `GOOGLE_APPLICATION_CREDENTIALS`). See `connectors/bigquery/auth.py`.

tests/test_cli_query_render.py

@@ -4,7 +4,7 @@ Three CLI paths surface BQ errors today:
 - `agnes query --remote` (cli/commands/query.py:_query_remote → /api/query)
 - `agnes query --register-bq` (cli/commands/query.py:_query_hybrid via
   RemoteQueryError, which wraps server-side BqAccessError)
-- `da fetch` / `agnes schema` / etc. (cli/v2_client.V2ClientError → v2 endpoints)
+- `agnes snapshot create` / `agnes schema` / etc. (cli/v2_client.V2ClientError → v2 endpoints)
 
 After the refactor they all call cli.error_render.render_error so analyst
 output is consistent and structured. Closes part of #160 §4.7.3.

tests/test_cli_snapshot_create.py

@@ -1,4 +1,4 @@
-"""Tests for `agnes snapshot create` (folded from `da fetch`)."""
+"""Tests for `agnes snapshot create`."""
 
 from typer.testing import CliRunner