Fix EF_SPDI decode crash: parse inner '80' TLVs, emit dict plmns

stk_test1 msg 14036 regression: READ BINARY of EF_SPDI returned
"No decoded data available" — _decode_spdi (added v1.16.0) parsed
the A3 container value as bare 3-byte records (missing the inner
'80' value TLVs) and returned a list of strings, while
_build_summary/_file_summary expects the EF_PLMNwAcT shape
(list of {mcc, mnc} dicts). The resulting TypeError aborted the
whole message decode — this was the source of the 28 "Decode
error ... string indices" messages seen across all sessions.

_decode_spdi now unwraps inner '80' TLVs (bare-records fallback
kept) and always returns {'plmns': [{mcc, mnc}...]}. Replay of all
33 sessions: decode exceptions 28 → 0 (2 remaining undecoded tpdu
are 1-byte truncated capture records, not decodable by nature).

Tests: +3 (standard inner-80 form, bare-records fallback, exact
stk_test1 regression via decode_message). 344 total. Version
1.17.1, SW cache simtrace-analyser-v25.

simtrace2_pysniff/server/decode.py

@@ -3243,19 +3243,32 @@ def _decode_smsp(raw, p1=None):
 
 
 def _decode_spdi(raw, p1=None):
-    """EF_SPDI (§4.2.66): 'A3' container with PLMN records (§0.3)."""
+    """EF_SPDI (§4.2.66): 'A3' container (or bare '80' value tags) with
+    3-byte PLMN records — same shape as EF_PLMNwAcT for _file_summary."""
     if all(b == 0xff for b in raw):
         return {'empty': True}
+    plmns = []
+
+    def collect(value):
+        for i in range(0, len(value) - 2, 3):
+            plmn = _decode_plmn(value[i:i + 3])
+            if plmn and plmn not in plmns:
+                plmns.append(plmn)
+
     for tag, _length, value in parse_tlv(raw):
         if tag == 0xA3:
-            plmns = []
-            for i in range(0, len(value) - 2, 3):
-                plmn = _decode_plmn(value[i:i + 3])
-                if plmn:
-                    plmns.append(f"{plmn['mcc']}-{plmn['mnc']}")
-            if plmns:
-                return {'plmns': plmns if len(plmns) > 1 else plmns[0]}
-    return {'raw': raw.hex().upper()}
+            got = False
+            for t2, _l2, v2 in parse_tlv(value):
+                if t2 == 0x80:
+                    collect(v2)
+                    got = True
+            if not got:
+                collect(value)  # bare records inside A3
+        elif tag == 0x80:
+            collect(value)
+    if not plmns:
+        return {'raw': raw.hex().upper()}
+    return {'plmns': plmns}
 
 
 def _decode_spn(raw, p1=None):