qtgui: consolidate workspace panels and global progress

[janhubicka]

Summary

• make transient progress presentation a WorkspaceWindow concern so running work remains visible independently of the selected tab/view
• keep progress operation state document-owned while routing workspace Stop/Cancel without changing the active MDI child
• consolidate detachable panel sections behind one ParameterPanel lifecycle instead of separate document/reference-view dock implementations
• simplify MainWindow, ImageViewWindow, and WorkspaceWindow ownership after the multiple-document/multiple-view extension
• preserve specialized-view boundaries while ordinary New Views continue to share document editing/panel state
• restore the complete source-document File menu in secondary views (Open, recent files/parameters, Save Parameters, Render, Exit), substituting only Close View for Close Window
• update .agents/qtgui.md and extend Qt GUI smoke coverage for progress across tab switches, File-menu parity, and detachable sections

Design

WorkspaceWindow owns top-level application chrome and progress presentation. MainWindow remains the owner of one logical document, processing state, undo and operations. Ordinary secondary views are presentations of that document; specialized/reference views remain constrained to their own compatible image operations.

Detachable sections use one reusable ParameterPanel lifecycle: detach, reattach-on-close, repeated detach, host migration, and teardown. A section always follows the actual top-level QMainWindow currently presenting its inspector. Thus an embedded document or reference view detaches into the workspace shell, while a detached presentation uses its own top-level window. Nested QMainWindow instances are never used as dock hosts.

CI follow-ups

The first ARM64 checking failure exposed the slanted-reference MTF ownership path. Qt 6.11 also rejected typed QObject::findChildren<DetachableSection *>() because the implementation-only helper intentionally has no Q_OBJECT; the intermediate fix removed that meta-object dependency, and detachable sections were made independent of QObject-child discovery.

A later ARM64 failure exposed the actual nested-host issue: the slanted-reference Sharpness panel had been pinned to an embedded ImageViewWindow. That pin was removed; reference diagnostics use the same actual-top-level-window rule as all other detachable sections.

The subsequent ARM64 ASan failure was in the smoke harness itself. The generic smoke cleanup timer could fire while the slower structured reference test was inside processEvents(), destroy the reference panel, and leave stale raw widget pointers in the test. Reference-panel objects crossing an event-loop turn are now guarded with QPointer.

The final review cleanup removes the remaining intermediate host-pinning API entirely, keeps progress-signal subscriptions tied to logical-document lifetime so detach/reattach cannot accumulate duplicate callbacks, and makes New View / slanted-reference smoke tests completion-driven. Their duration is now only a failure watchdog: successful structured checks quit immediately, and a watchdog expiry reports a timeout instead of destroying test widgets underneath active assertions. No sanitizer or behavioral assertions were removed.

Commits

• fc6aded0091e4014ef113b89f9d74a3262a908bc — workspace/global-progress and uniform detachable-section cleanup
• 134e8622b4bf6813d96d996a4e98066bab10fc77 — reference-detachment sanitizer fix and secondary File-menu parity
• b9908f5f03c92a60ad2f3bda0c87053837dea655 — avoid Qt meta-object casts for implementation-only detachable sections
• 82a7fcb90fedcedc67ea9900d28a1bc110fb9e18 — track detachable sections independently of layout parenting
• 9a53b02eca8aeed2498a114ac851d5322a24a25b — host detachable sections in the actual top-level window
• 4a42f3384f5765b9b536117ceeae18c58a57cb5b — guard reference smoke widget lifetimes across event-loop turns
• 166315d8e38d96169cc6487a440de30e08f1cae7 — initial sanitizer-smoke lifetime follow-up
• dabc1083f4ace1d3660b6197881220d94afdbb79 — tighten workspace ownership lifetimes and make structured smoke completion-driven