feat(aethercontrol): double-click to latch / unlatch (replaces click+ESC asymmetry)

[ten9876]

Summary

Changes AetherControl's virtual FlexControl knob from a click-to-latch / Escape-to-unlatch UX to a double-click for both directions, with Escape kept as a secondary safety release.

Why

Operators report losing track of the release path. First-time users miss the small "Press ESC to release" hint at the bottom of the dialog and feel stuck with the cursor captured.

What changed

Action	Before	After
Latch	Single left-click on wheel	Double-click on wheel
Unlatch	ESC key	Double-click on wheel (primary) or ESC (secondary safety)
Single click on wheel	Latched	No-op (event accepted to suppress accidental window drag)

Updated user-visible strings:

• Resting hint: "Double-click the knob to capture circular tuning."
• Armed hint: "Mouse locked to FlexControl. Double-click the knob to release (or press ESC)."
• Accessible description mirrors the new gesture.

ESC stays as a backup for the edge case where the cursor ended up offscreen and can't get back over the knob to double-click.

Attribution

AetherControl original implementation by @rfoust (#2888); FlexControl wheel UX overhaul also by @rfoust (#3029). This change preserves the existing wheel-feel work and only touches the capture/release gesture.

Test plan

• Linux build clean
• CI: build / check-paths / check-windows / CodeQL
• Manual: open AetherControl (Settings → FlexControl), single-click on wheel does nothing, double-click captures, double-click again releases, ESC still releases as backup

73, Jeremy KK7GWY & Claude (AI dev partner)

🤖 Generated with Claude Code

[aethersdr-agent]

Thanks @ten9876 — agree the click-to-latch / Esc-to-unlatch asymmetry was a real discoverability cliff, and double-click as a single binding is a nice fix. Implementation looks clean: the press-event no-op is correctly still accept()-ing so it doesn't fall through to a window drag, mouseDoubleClickEvent handles both directions, and the explanatory comments capture the why well.

One inconsistency worth fixing in this PR

The in-knob "armed" badge painted at src/gui/FlexControlDialog.cpp:621 still reads:

const QString hint = QStringLiteral("Press Esc\nto release");

That overlay is the most prominent capture-state cue (centered on the wheel, accented border) and now contradicts the updated bottom-of-dialog hint and accessible description, both of which name double-click as the primary release path. A first-time captured user will see "Press Esc to release" front-and-centre and never discover that double-click also works — which is the exact UX gap this PR is trying to close. Suggest something like "Double-click\nor press Esc" (or two lines, whichever still fits the badge rect at the existing point size).

Minor observations, not blockers

• mousePressEvent only checks isEnabled() and not m_captured — fine, since while captured the press just accepts and the double-click event drives the release, but worth a mental note in case anyone adds press-side behavior later.
• Test plan still has the CI / manual boxes unchecked; once Linux build + manual smoke confirm, this is ready.

Nice quality-of-life improvement. Just the badge text update and this is good to go from my end.

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