Give the work queue its own Redis root, and pin what the suite runs as

The queue shared the `pipeline:` prefix with flow state, so `RedisState.clear()`
could DEL the queue stream and `keys()` enumerated queue entries — only callers
filtering `__`-prefixed names kept it safe. It moves to `queue:` without a
migration: whatever is in flight at the upgrade is dropped once, documented in
DEPLOY.md rather than papered over.

Alongside it: `pool_pre_ping`, so a connection idle across a Postgres restart
costs a round trip instead of a failed request; the test suite pins
ENVIRONMENT=local and DOMAIN=localhost itself rather than inheriting a
deployment's .env; and `depth` leaves the queue stats, where it reported the
capped journal length as if it were a backlog.

ALERTS_FILE and PANELS_FILE now point at /data. They defaulted to a path on no
volume, so alert routing and every wall-panel pairing were living in the
container's writable layer and vanishing on each rebuild. Carrying the existing
files across is a manual step; DEPLOY.md has it.

development.md was still the upstream template — compose.override.yml,
localhost.tiangolo.com, `docker compose watch` as the dev flow — and said
nothing about the Playwright suite. Rewritten against what the Makefiles
actually do. deployment.md was template text too, duplicating the root
DEPLOY.md, and is gone.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Uq8mtNb97A7praJLyeEYgs

backend/tests/__init__.py

@@ -16,3 +16,8 @@ os.environ["MCP_ENABLED"] = "false"
 # The private seeding endpoints are opt-in; the suite is one of the two places
 # (with the dev stack) where they are meant to work.
 os.environ["PRIVATE_API_ENABLED"] = "true"
+# The suite is the development configuration by definition: `/private` is
+# gated on it (app/api/routes/private.py) and the MCP host allow-list is
+# built from DOMAIN (app/mcp/http.py), while the tests speak to api.localhost.
+os.environ["ENVIRONMENT"] = "local"
+os.environ["DOMAIN"] = "localhost"