Relax CID=0 filter: allow partially decoded cells with valid MCC/MNC

CID=0 with valid MCC/MNC means the scanner found the cell but didn't
decode System Information 3/4 (which carries the Cell ID). These are
still valid towers worth displaying. Only filter when MCC=0 AND MNC=0
(truly unidentified signals).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

routes/gsm_spy.py

@@ -1130,10 +1130,12 @@ def parse_grgsm_scanner_output(line: str) -> dict[str, Any] | None:
         if 'ARFCN' in fields and 'CID' in fields:
             cid = int(fields.get('CID', 0))
             mcc = int(fields.get('MCC', 0))
+            mnc = int(fields.get('MNC', 0))
 
-            # Skip entries with no decoded cell identity (CID=0 means no cell info)
-            if cid == 0 or mcc == 0:
-                logger.debug(f"Skipping unresolved ARFCN (CID={cid}, MCC={mcc}): {line}")
+            # Only skip entries with no network identity at all (MCC=0 AND MNC=0)
+            # CID=0 with valid MCC/MNC is a partially decoded cell - still useful
+            if mcc == 0 and mnc == 0:
+                logger.debug(f"Skipping unidentified ARFCN (MCC=0, MNC=0): {line}")
                 return None
 
             # Freq may have 'M' suffix (e.g. "925.2M")
@@ -1146,7 +1148,7 @@ def parse_grgsm_scanner_output(line: str) -> dict[str, Any] | None:
                 'cid': cid,
                 'lac': int(fields.get('LAC', 0)),
                 'mcc': mcc,
-                'mnc': int(fields.get('MNC', 0)),
+                'mnc': mnc,
                 'signal_strength': float(fields.get('Pwr', -999)),
                 'timestamp': datetime.now().isoformat()
             }

tests/test_gsm_spy.py

@@ -71,18 +71,27 @@ class TestParseGrgsmScannerOutput:
         result = parse_grgsm_scanner_output(line)
         assert result is None
 
-    def test_cid_zero_filtered(self):
-        """Test that CID=0 entries (no decoded cell) are filtered out."""
+    def test_no_identity_filtered(self):
+        """Test that MCC=0/MNC=0 entries (no network identity) are filtered out."""
         line = "ARFCN: 115, Freq: 925.0M, CID: 0, LAC: 0, MCC: 0, MNC: 0, Pwr: -100"
         result = parse_grgsm_scanner_output(line)
         assert result is None
 
-    def test_mcc_zero_filtered(self):
-        """Test that MCC=0 entries (no decoded identity) are filtered out."""
+    def test_mcc_zero_mnc_zero_filtered(self):
+        """Test that MCC=0/MNC=0 even with valid CID is filtered out."""
         line = "ARFCN: 113, Freq: 924.6M, CID: 1234, LAC: 5678, MCC: 0, MNC: 0, Pwr: -90"
         result = parse_grgsm_scanner_output(line)
         assert result is None
 
+    def test_cid_zero_valid_mcc_passes(self):
+        """Test that CID=0 with valid MCC/MNC passes (partially decoded cell)."""
+        line = "ARFCN: 115, Freq: 958.0M, CID: 0, LAC: 21864, MCC: 234, MNC: 10, Pwr: -51"
+        result = parse_grgsm_scanner_output(line)
+        assert result is not None
+        assert result['cid'] == 0
+        assert result['mcc'] == 234
+        assert result['signal_strength'] == -51.0
+
     def test_valid_cid_nonzero(self):
         """Test that valid non-zero CID/MCC entries pass through."""
         line = "ARFCN: 115, Freq: 925.0M, CID: 19088, LAC: 21864, MCC: 234, MNC: 10, Pwr: -58"