mvp #46: wire ASAP_CONTROLLER_URL env, generalize freshness probe filter - #114

`asap-query-engine` ships with `--controller-endpoint` for capability-
miss notifications back to the controller (criterion #2 reverse
channel). The MVP overlay sets `ASAP_CONTROLLER_URL` in
`deploy/docker-compose/base.yml`, but `clap` only read the flag —
not the env var — so the backend silently never notified the
controller. Added `env = "ASAP_CONTROLLER_URL"` to the arg attribute
so the existing compose env var is honored.

Also generalized `routing/freshness_probe_cache.rs` so any metric
whose name *contains* `freshness_probe_` is captured by the RAM
short-circuit (was: literal prefix `http_freshness_probe_`).
User-extensible probe families (e.g. `latency_freshness_probe_*`)
now hit the cache without a code change. The MVP demo's three
canonical probes (`http_freshness_probe_{raw,warm,archive}`) still
match — verified by the existing
`is_freshness_probe_matches_three_demo_spellings` test.

Verification:
- `cargo build --manifest-path asap-query-engine/Cargo.toml`: clean
- `cargo test --lib freshness_probe_cache`: 8 passed

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>