The event-report waveform plot scaled each geo lane to its own peak, so a small
channel filled its lane looking as big as a large one — and the "Geo: X in/s/div"
footer only reflected whichever channel was checked first, so its div value was
wrong for the other two. Now all three geo lanes share ONE symmetric scale =
max |sample| across them (padded, 0.05 in/s floor), matching the event modal and
BW's single amp/div; the footer reflects that shared scale. Mic keeps its own psi
scale. Big events are unchanged (e.g. BE12844 stays 0.185 in/s/div).
Test-first: tests/test_report_pdf_geo_scale.py (shared scale + floor), 2 tests.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YDXjZCr4RqT2U3QvMDhgzf
