Add per-command response decoders (FCP, AUTH, TERMINAL RESPONSE)

decode.py:
- _decode_fcp: FCP/FCI/FMD template — full bit-level file descriptor
  (TS 102 221 Table 11.5: file type, structure, shareable, data coding,
  record length, num records), file ID (+ KNOWN_FIDS name), DF name,
  SFI, life cycle
- _decode_auth: GSM SRES+Kc, or 3G tag DB (RES/CK/IK/KC) / DC (AUTS)
- _decode_tr_result: TERMINAL RESPONSE Result TLV (code + name)
- _decode_response_for(ins, data): GET RESPONSE decodes its body using
  the previous command's INS (SELECT→FCP, AUTHENTICATE→auth)
- decode_message wires response decoding for TR and GET RESPONSE

database.py: prev context now carries 'ins' (INS byte) via
_context_from_decoded, used by GET RESPONSE response decoding

tests: FCP, AUTH (GSM/3G), TR result, GET RESPONSE wiring (57 total)

simtrace2_pysniff/server/database.py

@@ -202,7 +202,16 @@ class Database:
         d = decode_sniff_msg(row[0], 'tpdu', 0)
         if not d:
             return None
-        return {'ins_name': d.get('ins_name'), 'sw1': (d.get('sw') or {}).get('sw1')}
+        return self._context_from_decoded(d)
+
+    def _context_from_decoded(self, d):
+        ins_hex = d.get('ins_hex')
+        ins = int(ins_hex, 16) if ins_hex else None
+        return {
+            'ins': ins,
+            'ins_name': d.get('ins_name'),
+            'sw1': (d.get('sw') or {}).get('sw1'),
+        }
 
     def _decode_rows(self, rows, initial_prev=None):
         msgs = []
@@ -211,9 +220,6 @@ class Database:
             msg = self._row_to_message(row, prev=prev)
             d = msg.get('decoded')
             if msg['type'] == 'tpdu' and d and d.get('ins_hex'):
-                prev = {
-                    'ins_name': d.get('ins_name'),
-                    'sw1': (d.get('sw') or {}).get('sw1'),
-                }
+                prev = self._context_from_decoded(d)
             msgs.append(msg)
         return msgs