Fix circular import, primary-admin NULL trap, and add gateway quota reset

Restores a working import graph and closes two data-correctness bugs, plus
adds a reset for the AI gateway's rolling 24h spend.

Circular import: database/__init__ -> engagement -> content -> utils ->
database made the package unimportable. get_project_devlog moves out of
database/engagement.py into content.py, where enrich_items already lives.

Primary administrator: _can_hold_primary_admin read is_active with
bool(row.get("is_active")), so an admin row whose is_active column is SQL
NULL (any row predating the column) was treated as deactivated and skipped.
Every other site defaults an unknown is_active to active; this one now does
too.

Profile JSON: xp_next_level and xp_progress_pct were computed but only put on
the top-level context, never on profile_user, so they serialised as null even
though UserOut declares them and the API docs document them as embedded there.

Gateway quota reset: a cap previously lifted only with the passage of time.
quota.reset upserts a watermark row into gateway_quota_resets, scoped by the
same three nullable dimensions as a quota rule, and spent_24h sums from
max(24h cutoff, watermark). No ledger row is deleted, so the cost analytics on
/admin/ai-usage stay intact. Reaches every surface: POST
/admin/gateway/quota-resets, a per-rule Reset spend button, the Devii tool
gateway_quota_reset (confirm-gated), devplace gateway quota reset, and the API
docs. Admin's Reset all quotas now stamps a global gateway watermark too,
which is what a caller stuck on "AI gateway daily quota exceeded" needed.

Startup: _backfill_gamification swept every xp=0 user on every boot in every
worker and could never converge, since a user with no content earns no XP.
It now intersects pending users with _milestone_candidates(). db.tables is a
live reflection, so it is hoisted out of the loops that probed it per row.

Docker: the dependency layer now depends on pyproject.toml only, so a source
edit no longer reinstalls every dependency and re-downloads Chromium.
Adds start_interval so the healthcheck probes during the start period, and a
docker-reload target, since docker-up does not restart an unchanged container.

Adds events.md, the audit event catalogue that README, CLAUDE.md, the quiz
docs and the tooling all referenced but which never existed: 288 keys across
28 categories, including the families built from a variable at the call site.

Test fixes: both devlog helpers dated post 0 as the newest while the tests
assumed post 2 was; a profile login posted username= to a form that takes
email=; a devlog assertion matched six buttons under strict mode; and the
primary-admin tests seeded founders newer than the back-dated fixture admin,
so they only passed without the api tier.

Full suite: 2989 passed, 1 skipped.

Makefile

@@ -138,7 +138,7 @@ DOCKER_GID ?= $(shell stat -c '%g' /var/run/docker.sock 2>/dev/null)
 export DEVPLACE_DATA_DIR
 export DOCKER_GID
 
-.PHONY: docker-build docker-up docker-down docker-logs docker-clean docker-prep ppy
+.PHONY: docker-build docker-up docker-reload docker-down docker-logs docker-clean docker-prep ppy
 
 # Build the single shared container image every instance runs. Build once;
 # rebuild only when ppy.Dockerfile, the sudo shim, or pagent change.
@@ -154,6 +154,10 @@ docker-build: docker-prep
 docker-up: docker-prep
 	$(COMPOSE) up -d
 
+docker-reload:
+	$(COMPOSE) restart app
+	$(COMPOSE) up -d --wait
+
 docker-down:
 	$(COMPOSE) down