pid_graph step 5 ran the TEXT label fallback for every edge without a
number. Once signal lines stopped carrying a fabricated number (3c0babf),
every pneumatic/electric run drawn by pid_line_draw entered it, and a
transmitter-to-controller run 12 mm above a labelled header came back as
line_number="100-P-1", number_source="label" — on both engines, with no
confidence field on edges to flag it.
The fallback now skips an edge that carries its own record (an
ACADMCP_PID payload: its `number: null` is the answer) and any
signal-class edge, payload or layer-classified (`signal_unknown`
included): LINE_NUMBER_RE is the pipe grammar, so a match near a signal
line always belongs to a neighbouring pipe. A foreign process line still
takes its label; a verbatim number on a signal line still reads back
from XDATA.
Tests: the finding's layout in test_pid_graph (engine-drawn signal beside
a labelled pipe, verbatim signal number, foreign electric and
signal_unknown lines beside a labelled foreign pipe) and the line_list
row in test_pid_deliverables — three of the four fail on the old reader.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd
