2026-07-03 — per-base quality track + FASTQ/QUAL exactness (v14)

Today’s slice finishes the quality story: a dedicated per-base quality bar track now sits under the trace, and export coverage was tightened with exact-value assertions for FASTQ and QUAL all-trimmed edge cases.

Per-base quality track

A new quality track renders one bar per visible base, aligned to each called peak. Bar height scales with PHRED score and colors are tiered (poor/fair/good/excellent) via theme tokens, so the track reads cleanly in both light and dark mode. The section is keyboard and screen-reader friendly and includes a toggle to collapse/expand the track without affecting sequence/export state.

Export consistency

FASTQ and QUAL export already flowed through the editable-base pipeline; this pass keeps that contract tight by asserting exact bytes for known outputs, including the all-trimmed case where sequence/quality bodies are intentionally empty after the header line.

Validation

The new layout unit tests assert exact x/height/tier mapping, including reverse-complement coordinate alignment. E2E checks verify the quality track is accessible/toggleable and that rendered bar heights at sampled x-positions match expected PHRED-derived values (not just a generic canvas ink sum).