feat(v0.6-tail-3): enforce OR-not-AND continuously -- close USGS direct-lookup leak + flag environmental config changes as restart-required

Gap 1 -- env_routes.lookup_usgs_site no longer creates a temporary
USGSStreamsAdapter to hit USGS.gov directly. When the env_store has no
native usgs adapter (because usgs.feed_source != native), the endpoint
returns HTTP 404 with a body that says "site lookup unavailable in
central-feed mode; values must be entered manually or sourced from
Central". This closes the AND-mode anti-pattern Central's v0.10.2
report flagged: meshai was in central-feed mode for usgs but the
lookup helper would still call USGS.gov directly the first time the
dashboard opened the Add-Gauge form.

Gap 2 -- config_routes.RESTART_REQUIRED_SECTIONS gains "environmental"
and the PUT handler now diffs the section before/after, returning
{saved, restart_required, changed_keys}. restart_required is true only
when there are actual changes AND the section is in the restart-required
set, so a no-op PUT to environmental never raises a false alarm.

Frontend wiring:
- New RestartBanner component (yellow top-of-main banner) listens to a
  meshai:restart-required CustomEvent + cross-tab storage event,
  persists across navigations via localStorage, shows changed_keys
  preview + Restart-now button (POSTs /api/system/restart) + dismiss.
- Layout.tsx mounts <RestartBanner /> above {children} so it surfaces
  on every page.
- Config.tsx saveSection() now calls notifyRestartRequired(changed_keys)
  alongside its existing setRestartRequired(true) when the API flags
  the section.
- GaugeSites.tsx probes /api/config/environmental at mount and shows a
  "USGS lookup" button next to the site_id input. The button is
  disabled with an explanatory tooltip when usgs.feed_source != native,
  and gracefully renders the 404 detail when the API returns 404 in
  central-feed mode -- enter-manually UX, no silent fallback.

Tests -- tests/test_or_arch_continuous.py (11 cases, all passing):
- USGS lookup 404 with no env_store / no native usgs adapter
- 502 on native-adapter exception
- 200 + payload on native-adapter happy path
- environmental in RESTART_REQUIRED_SECTIONS
- PUT environmental with changed feed_source -> restart_required:true
  + changed_keys list including foo.feed_source dotted path
- PUT bot (non-restart section) -> restart_required:false
- No-op PUT to bot / environmental -> restart_required:false, empty
  changed_keys
- _diff_keys helper unit tests (nested dicts, list-element changes)

Why this matters: per the Spokane post-mortem and Central's v0.10.2
response, both sides need belt-and-suspenders against transient
AND-modes. meshai's static OR enforcement at env_store boot is the
runtime guard; this commit makes the GUI honor it continuously --
the lookup helper can't sneak past it any more, and the user is told
explicitly that an environmental config change does not take effect
until the container restarts.

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

tests/test_or_arch_continuous.py

@@ -0,0 +1,181 @@
+"""v0.6-tail-3 tests: env_routes 404 + config_routes restart_required diff."""
+from __future__ import annotations
+
+from types import SimpleNamespace
+from unittest.mock import MagicMock
+
+import pytest
+from fastapi import FastAPI
+from fastapi.testclient import TestClient
+
+from meshai.config import Config
+
+
+# ============================================================================
+# Gap 1 -- env_routes lookup_usgs_site 404 when feed_source != native
+# ============================================================================
+
+
+def _build_app_with_env_store(env_store):
+    """Mount the env router on a minimal FastAPI app w/ env_store on state."""
+    from meshai.dashboard.api.env_routes import router as env_router
+    app = FastAPI()
+    app.state.env_store = env_store
+    app.state.config = Config()
+    app.include_router(env_router, prefix="/api")
+    return app
+
+
+def test_usgs_lookup_404_when_no_env_store():
+    app = _build_app_with_env_store(env_store=None)
+    client = TestClient(app)
+    r = client.get("/api/env/usgs/lookup/13139510")
+    assert r.status_code == 404
+
+
+def test_usgs_lookup_404_when_no_native_usgs_adapter():
+    """Central-feed mode: env_store exists but adapters['usgs'] is missing."""
+    env_store = SimpleNamespace(_adapters={})  # no usgs adapter
+    app = _build_app_with_env_store(env_store)
+    client = TestClient(app)
+    r = client.get("/api/env/usgs/lookup/13139510")
+    assert r.status_code == 404
+    body = r.json()
+    # Body must explain the central-feed mode reason so the UI can switch
+    # the form to manual-entry mode.
+    assert "central" in body.get("detail", "").lower()
+    assert "manual" in body.get("detail", "").lower()
+
+
+def test_usgs_lookup_calls_native_adapter_when_available():
+    """When the env_store has a native usgs adapter, lookup proxies to it."""
+    fake_adapter = MagicMock()
+    fake_adapter.lookup_site = MagicMock(return_value={
+        "site_id": "13139510",
+        "name": "Big Lost River near Mackay",
+        "lat": 43.91,
+        "lon": -113.62,
+    })
+    env_store = SimpleNamespace(_adapters={"usgs": fake_adapter})
+    app = _build_app_with_env_store(env_store)
+    client = TestClient(app)
+    r = client.get("/api/env/usgs/lookup/13139510")
+    assert r.status_code == 200
+    assert r.json()["name"] == "Big Lost River near Mackay"
+    fake_adapter.lookup_site.assert_called_once_with("13139510")
+
+
+def test_usgs_lookup_502_on_adapter_exception():
+    """A failure inside the native adapter surfaces as 502, not 200+error."""
+    fake_adapter = MagicMock()
+    fake_adapter.lookup_site = MagicMock(side_effect=RuntimeError("upstream timeout"))
+    env_store = SimpleNamespace(_adapters={"usgs": fake_adapter})
+    app = _build_app_with_env_store(env_store)
+    client = TestClient(app)
+    r = client.get("/api/env/usgs/lookup/13139510")
+    assert r.status_code == 502
+
+
+# ============================================================================
+# Gap 2 -- config_routes RESTART_REQUIRED_SECTIONS + changed_keys diff
+# ============================================================================
+
+
+@pytest.fixture
+def config_app(tmp_path, monkeypatch):
+    """FastAPI app w/ config_routes mounted; uses a tmp config dir."""
+    from meshai.dashboard.api.config_routes import router as config_router
+
+    # save_section needs a real config dir to write to.
+    cfg_dir = tmp_path / "cfg"
+    cfg_dir.mkdir()
+    (cfg_dir / "config.yaml").write_text("# stub\n")
+
+    app = FastAPI()
+    app.state.config = Config()
+    app.state.config_path = str(cfg_dir / "config.yaml")
+    app.include_router(config_router, prefix="/api")
+    return app
+
+
+def test_environmental_in_restart_required_sections():
+    from meshai.dashboard.api.config_routes import RESTART_REQUIRED_SECTIONS
+    assert "environmental" in RESTART_REQUIRED_SECTIONS
+
+
+def test_put_environmental_returns_restart_required_with_changed_keys(config_app):
+    """A PUT to environmental that changes feed_source returns
+    restart_required=true + the dotted changed_keys list."""
+    client = TestClient(config_app)
+
+    # Fetch current environmental.
+    cur = client.get("/api/config/environmental")
+    assert cur.status_code == 200
+    body = cur.json()
+    # Mutate firms.feed_source from "native" (default) to "central".
+    body["firms"]["feed_source"] = "central"
+
+    r = client.put("/api/config/environmental", json=body)
+    assert r.status_code == 200
+    result = r.json()
+    assert result["saved"] is True
+    assert result["restart_required"] is True
+    # The dotted key must be present.
+    assert any(k.endswith("firms.feed_source") for k in result["changed_keys"]), (
+        f"changed_keys missing firms.feed_source: {result['changed_keys']}"
+    )
+
+
+def test_put_non_restart_section_returns_restart_required_false(config_app):
+    """A PUT to bot (not restart-required) returns restart_required=false."""
+    client = TestClient(config_app)
+    cur = client.get("/api/config/bot").json()
+    cur["name"] = "NEW_NAME"
+    r = client.put("/api/config/bot", json=cur)
+    assert r.status_code == 200
+    result = r.json()
+    assert result["restart_required"] is False
+    assert "bot.name" in result["changed_keys"]
+
+
+def test_put_with_no_changes_returns_empty_changed_keys(config_app):
+    """A no-op PUT returns restart_required=false + empty changed_keys."""
+    client = TestClient(config_app)
+    cur = client.get("/api/config/bot").json()
+    r = client.put("/api/config/bot", json=cur)
+    assert r.status_code == 200
+    result = r.json()
+    assert result["restart_required"] is False
+    assert result["changed_keys"] == []
+
+
+def test_put_environmental_no_change_does_not_flag_restart(config_app):
+    """Even though environmental is restart-required, an unchanged PUT must
+    not show restart_required=true. The restart-required state is
+    contingent on real diff."""
+    client = TestClient(config_app)
+    cur = client.get("/api/config/environmental").json()
+    r = client.put("/api/config/environmental", json=cur)
+    assert r.status_code == 200
+    result = r.json()
+    assert result["restart_required"] is False
+    assert result["changed_keys"] == []
+
+
+def test_diff_keys_nested():
+    """Spot-check the _diff_keys helper on nested dicts + lists."""
+    from meshai.dashboard.api.config_routes import _diff_keys
+    before = {"a": 1, "b": {"x": 1, "y": 2}, "c": [1, 2, 3]}
+    after  = {"a": 1, "b": {"x": 9, "y": 2}, "c": [1, 2, 3, 4]}
+    keys = _diff_keys(before, after, prefix="root")
+    assert "root.b.x" in keys
+    assert "root.c" in keys           # list length differs -> bracketless
+    assert "root.a" not in keys
+
+
+def test_diff_keys_list_element_changes():
+    from meshai.dashboard.api.config_routes import _diff_keys
+    before = {"a": [1, 2, 3]}
+    after  = {"a": [1, 9, 3]}
+    keys = _diff_keys(before, after, prefix="cfg")
+    assert "cfg.a[1]" in keys