fix(telemetry): usage readout grouped by a rebuilt CASE — group by the label instead (#2663 root cause)

CI's new integration tests reproduced the outage on a clean database and
named the half: the writes land fine, and usage_for_notes fails on EVERY
call. The GROUP BY rebuilt the ambient case() expression, and asyncpg's
expanding IN-parameters give each instance its own bind names — so Postgres
sees a SELECT expression the GROUP BY doesn't cover and rejects the query
with a GroupingError, which the old code swallowed into zeros. One labelled
expression, grouped by its label. The deployed table has been accumulating
events all along; history appears as soon as this deploys.

Also: the two hook-execution tests now run with the real PATH and skip
when the hook's tools are absent (the restricted-PATH convention next door
is for silence contracts, where empty-for-the-wrong-reason still passes) —
and the unit lane installs jq so 'skip' never quietly becomes 'nowhere'.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.forgejo/workflows/ci.yml

@@ -225,6 +225,16 @@ jobs:
           UV_PROJECT_ENVIRONMENT: /opt/venv
         run: uv sync --locked --extra dev
 
+      # The hook-EXECUTION tests (test_write_path_trigger's nudge pair) run the
+      # real bash hook, which exits silently without jq — and those tests skip
+      # rather than fail when it's absent, so without this step they would
+      # quietly never be verified anywhere (ci-python ships without jq; same
+      # install the Plugin hooks job does).
+      - name: Install jq for hook execution tests
+        run: |
+          apt-get update -qq
+          apt-get install -y -qq --no-install-recommends jq
+
       - name: Run tests
         # Integration tests (real Postgres) run in the `integration` job below.
         run: /opt/venv/bin/python -m pytest tests/ -q -m "not integration"