fix(peaks): peak marks follow chemical-shift reference edits

[Limdongcheng]

Root cause

PeakMark stored its x as a finished-spectrum snapshot, so editing a Reference step shifted the whole ppm axis while every existing mark stayed at the old coordinate — visibly detached from its peak.

Fix

Marks now store the uncalibrated position (finished x minus the pipeline's reference offset at pick time) and every reader adds the current offset back through PeakSet::resolve(offset), fed by the new Dataset::peak_reference_offset_ppm() — the pipeline's single semantic outlet chemical_shift_reference_offset_ppm, previously used only by CRAFT (tables calibrate by zero).

This is the lifecycle-copy option: the calibration lives once, in the pipeline, and marks follow any Reference edit — including undo/redo of the processing step — without being rewritten, so no mark-translation action or migration exists. Both write paths (manual picks and detection on the finished trace) subtract the current offset symmetrically; de-duplication compares in uncalibrated space.

Persisted mark coordinates change meaning; the format stays v1 with no compatibility reader, per repository policy. y deliberately remains a pick-time intensity snapshot: reference edits never change intensities, and refreshing y after re-phasing or normalization is an orthogonal concern.

Tests

Regression tests: mark → reference edit → resolved ppm follows the shifted trace and its default label; picks on an already-referenced spectrum round-trip through the uncalibrated store. cargo pr-check passes.

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Part 5 of the stack, based on fix/peak-snap (#5). The final part, the Reference on-plot pick (#1), is based on this branch.

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