refactor: create pm3py/trace/ for shared trace infrastructure

Trace buffer parsing, protocol decoders, NDEF annotation, and
formatting are firmware-level features shared by sniff, sim, and
reader modes — not sniff-specific. Moves these from sniff/ into
trace/. sniff/ retains only SniffSession (orchestration) and
re-exports trace symbols for convenience.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

pm3py/core/hf_iso15.py

@@ -3,13 +3,13 @@ import struct
 from .protocol import Cmd
 from .transport import PM3Transport, PM3Error
 
-# Re-export sniff symbols for backward compat with existing test imports
-from ..sniff.trace import parse_tracelog, TRACELOG_HDR_SIZE
-from ..sniff.decode_iso15 import (
+# Re-export trace symbols for backward compat with existing test imports
+from ..trace import (
+    parse_tracelog, TRACELOG_HDR_SIZE,
     decode_15693_request, decode_15693_response, decode_15693,
+    decode_ndef_annotation,
+    format_sniff_line,
 )
-from ..sniff.ndef import decode_ndef_annotation
-from ..sniff.format import format_sniff_line
 
 # ISO15 PM3 flags
 ISO15_CONNECT = 0x01

pm3py/sniff/__init__.py

@@ -1,9 +1,13 @@
-"""pm3py.sniff — Sniff sessions, trace parsing, protocol decoders, formatting."""
+"""pm3py.sniff — Sniff sessions (orchestrate sniff → download → decode → format)."""
 from .session import SniffSession
-from .trace import parse_tracelog, TRACELOG_HDR_SIZE
-from .decode_iso15 import decode_15693, decode_15693_request, decode_15693_response
-from .ndef import decode_ndef_annotation
-from .format import format_sniff_line
+
+# Re-export trace symbols for convenience
+from ..trace import (
+    parse_tracelog, TRACELOG_HDR_SIZE,
+    decode_15693, decode_15693_request, decode_15693_response,
+    decode_ndef_annotation,
+    format_sniff_line,
+)
 
 __all__ = [
     "SniffSession",

pm3py/sniff/session.py

@@ -3,8 +3,8 @@ import sys
 
 from ..core.protocol import Cmd, PM3_CMD_DATA_SIZE
 from ..core.transport import PM3Transport, encode_ng_frame
-from .trace import parse_tracelog
-from .format import format_sniff_line
+from ..trace import parse_tracelog
+from ..trace.format import format_sniff_line
 
 
 class SniffSession:

pm3py/trace/__init__.py

@@ -0,0 +1,12 @@
+"""pm3py.trace — Firmware trace buffer infrastructure (shared by sniff, sim, reader)."""
+from .trace import parse_tracelog, TRACELOG_HDR_SIZE
+from .decode_iso15 import decode_15693, decode_15693_request, decode_15693_response
+from .ndef import decode_ndef_annotation
+from .format import format_sniff_line
+
+__all__ = [
+    "parse_tracelog", "TRACELOG_HDR_SIZE",
+    "decode_15693", "decode_15693_request", "decode_15693_response",
+    "decode_ndef_annotation",
+    "format_sniff_line",
+]