Refactor canvas utility tools for production reliability

[dovvnloading]

Summary

• Fix the QtAwesome frame construction crash and harden Frame/Container membership invariants.
• Add exact group geometry persistence with stable IDs and preserve collapsed/expanded state on restore.
• Introduce a shared utility operation lifecycle with bounded context snapshots, cancellation, chat-epoch stale-result guards, provenance, source links, and durable utility saves.
• Harden Notes with stable metadata, bounded content, undo/redo editing, safe color-picker interactions, and scene-change scheduling.
• Include utility items in search, highlighting, select-all, and group workflows.

Validation

• python -m compileall -q graphlink_app
• python -m pytest -q --disable-warnings --maxfail=1 — 428 passed
• Headless Qt smoke: real Frame/Container construction, scene rendering, persistence round-trip, and group invariant validation.

The local proposal remains intentionally excluded from the public repository under ignored doc/.