Feature: Update RxMER visual and sync generated docs

- Add CM card modulation-count chart while keeping CM RxMER chart
- Adapt modulation count extraction to new analysis schema location
- Simplify visual text by removing redundant per-card frequency details
- Move frequency range and spacing to channel header metadata
- Remove ChannelWidth wording from window label
- Shorten modulation chart y-axis label for readability
- Sync PyPNM-CMTS collection visualizer content from source visual
- Regenerate visual docs and preview outputs to clear drift checks
- Update RxMER sample JSON fixture with latest capture dataset - 2026-03-06 11:36:35

Author: mgarcia01752