area_context v2 + Maps place verification (server-26#36, #37)

#36 — the correction pass shipped in 58efdbd was right, its reference-data
shape was not. One shape now, at both scopes, every field nullable:

  area_context: { municipality?, county?, state?,
                  center?, radius_km?, resolved_from?, resolved_at?,
                  local_knowledge?: [{term, meaning}] }

`state` closes the ambiguity that made "Ossining" a national guess.
`local_knowledge` replaces roads[]/landmarks[], which could not hold
intersections, schools or nicknames and carried no meanings — `11-X-ray` is
useless alone, `11-X-ray — MTA PD patrol unit` is what a corrector can act on.
Pre-#36 roads[]/landmarks[] are read forward as bare terms so nothing an
operator already entered is lost.

Nullability is the mechanism: which scope gets filled is the operator's
declaration of how homogeneous the system is. One town — fill it once at system
level. Statewide — leave it blank and fill each talkgroup.

The backend owns the derived anchor. PUT /systems/{id} merges config.talkgroups[]
against what is stored instead of writing the client's blob verbatim, which
would have erased the anchor and the pending queue — the same defect as the
ten_codes wipe.

#37 — Maps as a verifier, not as prompt stuffing. The corrector emits its
location nouns; each is geocoded against the talkgroup's anchor, and on a miss
we look for a sound-alike that does resolve there, correct to it, and propose
{term, meaning} to that talkgroup. Cost scales with location nouns, not calls.

No anchor means SKIP. An area too wide to discriminate stores no anchor at all,
because a statewide radius would confirm anything inside it — verification that
passes everything is worse than none, since it reads as a check in the data.

Also re-anchors _geocode_location, which rejected results >40km from the NODE
(server-26#6). An antenna is not a jurisdiction; distance-from-node was always
a stand-in for the anchor and is now only the fallback.

The induction loop proposes at talkgroup level and never promotes. Blast
radius: a wrong term on a channel misleads that channel, the same term
system-wide misleads one 400km away on a statewide system.

38 new tests; 240 pass. Frontend typechecks clean.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

drb-c2-core/tests/test_transcript_correction.py

@@ -21,14 +21,24 @@ from app.internal import transcript_correction as tc
 SYSTEM = {
     "vocabulary": ["Croton-Harmon", "Metro-North"],
     "ten_codes": {"10-4": "acknowledged", "10-13": "officer needs assistance"},
-    "area_context": {"county": "Westchester", "roads": ["Route 9", "Saw Mill Parkway"]},
+    "area_context": {
+        "county": "Westchester",
+        "state": "New York",
+        "local_knowledge": [
+            {"term": "Route 9", "meaning": "north-south state highway"},
+            {"term": "Saw Mill Parkway"},
+        ],
+    },
     "config": {
         "talkgroups": [
             {
                 "id": 9048,
                 "name": "Ossining - Police Dispatch",
                 "vocabulary": ["Snowden Avenue", "Croton-Harmon"],
-                "area_context": {"municipality": "Ossining", "landmarks": ["Sing Sing"]},
+                "area_context": {
+                    "municipality": "Ossining",
+                    "local_knowledge": [{"term": "Sing Sing", "meaning": "state prison"}],
+                },
             },
             {"id": 9600, "name": "Harrison - Police/EMS Dispatch"},
             {"id": 9563, "ten_codes": {"10-4": "on scene"}},
@@ -83,6 +93,7 @@ async def test_talkgroup_without_own_data_inherits_system():
         ctx = await tc.resolve_context("sys-1", 9600)
     assert ctx["vocabulary"] == ["Croton-Harmon", "Metro-North"]
     assert any("Westchester" in line for line in ctx["area_lines"])
+    assert ctx["area"].get("municipality") is None, "inherits, invents nothing"
 
 
 @pytest.mark.asyncio
@@ -105,7 +116,10 @@ async def test_missing_scope_is_not_an_error(system_id, tgid):
 async def test_unconfigured_system_yields_empty_context():
     with _system(doc=None):
         ctx = await tc.resolve_context("sys-1", 9048)
-    assert ctx == {"vocabulary": [], "ten_codes": {}, "area_lines": []}
+    assert ctx == {
+        "vocabulary": [], "ten_codes": {}, "area_lines": [],
+        "area": {}, "system_area": {}, "tg_area": {},
+    }
 
 
 # ── Correction behaviour ────────────────────────────────────────────────────
@@ -207,5 +221,7 @@ async def test_reference_data_reaches_the_prompt():
         await tc.correct("c1", "x y z w", None, system_id="sys-1",
                          talkgroup_id=9048, talkgroup_name="Ossining - Police Dispatch")
     p = seen["prompt"]
-    assert "Snowden Avenue" in p and "Sing Sing" in p and "Ossining - Police Dispatch" in p
+    assert "Snowden Avenue" in p and "Ossining - Police Dispatch" in p
+    assert "Sing Sing — state prison" in p, "a term without its meaning is half the information"
+    assert "Ossining, Westchester, New York" in p, "state must reach the prompt (server-26#36)"
     assert "10-13=officer needs assistance" in p