feat(central): v0.5.4 -- region-aware subscriptions using Central v0.9.20 regional subjects

Pre-v0.5.4 every Central subscription used a bare wildcard (central.wx.>,
central.fire.>, central.traffic.>, central.quake.>, central.hydro.>,
central.space.>), so a Magic Valley operator flipping nws -> central was
in fact subscribing to the all-US firehose and discarding 95% of events
locally. Central v0.9.20 (2026-05-28) added per-region subject suffixes
so the firehose can be filtered server-side. This wires meshai to use them.

Backend (meshai/central/consumer.py):
- New _subjects_for(adapter, region) replaces the static ADAPTER_SUBJECTS
  dict. ADAPTER_SUBJECTS is retained as an alias to _SUBJECTS_BARE for any
  legacy importers; the dispatcher path is unchanged.
- Per-adapter subject patterns (region='us.id' default):
    nws        -> central.wx.alert.us.id.>     (region BEFORE wildcard)
    usgs_quake -> central.quake.event.>.us.id  (region AFTER wildcard)
    firms      -> central.fire.hotspot.>.us.id
    fires      -> central.fire.incident.id.>   (state token at fixed depth)
                  central.fire.perimeter.id.>
    traffic    -> central.traffic.>.id          (bare state, no us. prefix)
    roads511   -> central.traffic.>.id          (shared with traffic, sub-adapter routing)
    usgs       -> central.hydro.>.us.id
                  central.hydro.>.unknown      (workaround until v0.9.20.1)
    swpc       -> central.space.>               (planetary; region ignored)
- Empty/None region falls back to bare wildcards (pre-v0.9.20 behaviour).
- _subject_owned() pulls region from env.central.region and routes through
  _subjects_for; v0.5.3 sub-adapter routing (owned-sources set) still
  applies on shared subjects like central.traffic.>.id.
- start() logs the active region at connect-time for ops visibility.

Config (meshai/config.py):
- CentralConsumerConfig.region: str = "us.id". One region per consumer
  applies to every central-flipped adapter; per-adapter overrides can
  land in v0.6 when there is a real use case.

Frontend (dashboard-frontend/src/pages/Environment.tsx):
- Central Connection panel gets a Region text input next to URL/Durable.
- EnvConfig.central type extended with region: string.
- Static bundle rebuilt; index-DCFmSeOM.js -> index-B24tHcYj.js.

Tests:
- tests/test_central_region_routing.py (new, 9 cases): asserts the exact
  v0.9.20 subject string for each adapter at region='us.id', the SWPC
  global-stays-global rule, the USGS .unknown workaround, the empty-region
  backward-compat fallback for all 8 adapters, and integration through
  CentralConsumer._subject_owned() with the default region.
- tests/test_central_consumer.py + tests/test_central_sub_adapter_routing.py:
  the two tests that asserted bare-wildcard subjects now set
  env.central.region = "" explicitly to preserve their original concern
  (no region semantics — backward-compat path only).

Why swpc stays global: space weather is planetary -- a CME is detected on
the sun, the geomagnetic response is hemispheric. There is no Idaho-only
solar event; subscribing per-region would only drop events we want.

Why hydro has the .unknown workaround: Central v0.9.20 leaves gauges
whose USGS state can't be inferred on central.hydro.>.unknown. Until
v0.9.20.1 backfills the state tag we subscribe to both filters to
avoid silently losing those rows. Idaho downstream-filtering on
data['_enriched']['usgs_site']['state'] is future v0.6 work.

Orthogonal to v0.5.2 dispatcher guards (staleness / cooldown / dedup)
and v0.5.3 sub-adapter routing: the region filter operates at the NATS
subscription layer (server-side), upstream of everything else.

Verified: pytest 327 passed (318 prior + 9 new region-routing tests);
py_compile clean; frontend build clean. Safe-mode preserved -- no toggle
enabled, no master enabled, no central enabled.

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

tests/test_central_region_routing.py

@@ -0,0 +1,88 @@
+"""v0.5.4: Central v0.9.20 region-aware subject building.
+
+Exercises `_subjects_for(adapter, region)` and the wiring through
+`CentralConsumer._subject_owned()`. The spec is hard-coded in the test
+strings on purpose so a future drift in the v0.9.20 subject scheme
+fails noisily here instead of silently shipping wrong filters.
+"""
+
+from meshai.central.consumer import (
+    CentralConsumer,
+    _subjects_for,
+    _SUBJECTS_BARE,
+)
+from meshai.config import EnvironmentalConfig
+
+
+# --------------------------------------------------------------------- per-adapter
+
+def test_subjects_for_nws_us_id():
+    """NWS: region BEFORE wildcard (matches alert.<region>.<...>)."""
+    assert _subjects_for("nws", "us.id") == ["central.wx.alert.us.id.>"]
+
+
+def test_subjects_for_usgs_quake_us_id():
+    """USGS quake: region AFTER wildcard."""
+    assert _subjects_for("usgs_quake", "us.id") == ["central.quake.event.>.us.id"]
+
+
+def test_subjects_for_firms_us_id():
+    """FIRMS hotspots: region AFTER wildcard, hotspot domain explicit."""
+    assert _subjects_for("firms", "us.id") == ["central.fire.hotspot.>.us.id"]
+
+
+def test_subjects_for_fires_us_id_uses_state_token():
+    """NIFC fires: state-only token at depth-4 for both incident + perimeter."""
+    assert _subjects_for("fires", "us.id") == [
+        "central.fire.incident.id.>",
+        "central.fire.perimeter.id.>",
+    ]
+
+
+def test_subjects_for_traffic_and_roads511_share_state_token():
+    """Traffic family: bare-state suffix (no us. prefix), shared by both adapters."""
+    assert _subjects_for("traffic",  "us.id") == ["central.traffic.>.id"]
+    assert _subjects_for("roads511", "us.id") == ["central.traffic.>.id"]
+
+
+def test_subjects_for_usgs_includes_unknown_workaround():
+    """USGS hydro: subscribes to BOTH the region-tagged filter and the
+    ".unknown" filter to cover gauges whose state Central v0.9.20 can't
+    infer yet (workaround until v0.9.20.1 backfills the tag)."""
+    assert _subjects_for("usgs", "us.id") == [
+        "central.hydro.>.us.id",
+        "central.hydro.>.unknown",
+    ]
+
+
+def test_subjects_for_swpc_stays_global():
+    """SWPC: space weather is planetary; region argument is ignored."""
+    assert _subjects_for("swpc", "us.id") == ["central.space.>"]
+    assert _subjects_for("swpc", "us.mt") == ["central.space.>"]  # same regardless
+    assert _subjects_for("swpc", "") == ["central.space.>"]
+
+
+# --------------------------------------------------------------------- backward compat
+
+def test_subjects_for_empty_region_falls_back_to_bare_wildcards():
+    """Empty/None region = pre-v0.9.20 behaviour for every adapter, byte-identical
+    to the legacy _SUBJECTS_BARE map. Adapters absent from the map return []."""
+    for adapter, expected in _SUBJECTS_BARE.items():
+        assert _subjects_for(adapter, "") == expected, f"empty region mismatch for {adapter}"
+        assert _subjects_for(adapter, None) == expected, f"None region mismatch for {adapter}"
+    # Unknown adapters return empty regardless of region.
+    assert _subjects_for("ducting", "us.id") == []
+    assert _subjects_for("avalanche", "") == []
+
+
+# --------------------------------------------------------------------- integration
+
+def test_central_region_default_propagates_to_consumer_subjects():
+    """Default region = 'us.id': flipping nws to central → consumer subscribes
+    to the region-aware subject, not the bare wildcard."""
+    env = EnvironmentalConfig()
+    assert env.central.region == "us.id"        # spec default
+    env.nws.feed_source = "central"
+    so = CentralConsumer(env, None)._subject_owned()
+    assert list(so.keys()) == ["central.wx.alert.us.id.>"]
+    assert so["central.wx.alert.us.id.>"] == {"nws"}