[MOR-1649] Restore passband overlay and filter-width resize on PBT-only radios

[morozsm]

Linear: https://linear.app/morozsm/issue/MOR-1649

Problem

The spectrum/waterfall passband overlay and its filter-width resize handle disappear on PBT-only radios. The scope adapter re-wraps already-derived filterPassband.ifShift in a raw main.ifShift field-status gate. IC-7300 has PBT but no raw if_shift, so the duplicate gate makes confirmedPassband false even when semantic passband authority is confirmed.

The bad double gate originated in PR #2355 (commit 250b1f…) and first became reachable through PR #2356 (commit e1be9c…). The exact candidate and current main are affected.

Acceptance criteria

• Preserve semantic authority-gated derived shift; fresh PBT-only IC-7300-shaped state with no raw if_shift produces centered ifShiftHz: 0 and a reachable passband overlay plus resize handle.
• Stale or missing PBT-derived passband remains hidden.
• FTX-1 native if_shift remains strictly gated by its own raw field authority.
• Scope adapter and component coverage use a true PBT-only profile witness; no optimistic passband truth, direct transport path, or model-name frontend branch.
• Scope stays at most 2–3 files; no broad refactor.
• RX-only IC-7300 and FTX-1 hardware reruns demonstrate truthful overlay visibility and filter-width resize; no TX action.

Relationships

Related: MOR-1291, MOR-1428, MOR-1494, MOR-1576, MOR-1642, MOR-1643, MOR-1644. No blocking dependency on MOR-1642 or MOR-1643.

Project fields

Status=Todo; WorkType=bug; Area=web-ui; Priority=P1; Phase=alpha; Owner=codex; Risk=medium; Size=S.

[morozsm]

RX-only hardware rerun on exact candidate db09073faf6159d115aa2690faa83ed66ba25605: FAIL on the remaining IC-7300 resize behavior.

The IC-7300 passband overlay, bounds, and resize handle were visible. Resizing jumped toward zero and then returned instead of providing smooth, continuous overlay response. Filter Width was restored to 3600.

The FTX-1 spectrum/overlay row is N/A: this hardware target does not expose a hardware waterfall/scope capability, so absence of that card is not a failure and the capability must remain unavailable.

Keep this issue Open and In Progress for the IC-7300 resize defect.