Automated Menu Generation & Pagination Engine

[ScottMorris]

Summary

Implement the automated generation engine for Spindle's new scene-driven menu system. This extension enables data-driven creation of complex menu sets from project metadata.

User-facing changes

• One-click generation: Add automated tools to create Chapter Grids, Title Shelves, and Track Menus directly from the authored document view.
• Auto-pagination: Support multi-page 'Menu Sets' when project data exceeds the physical hardware limits or visual budget.
• Theme selection: Allow users to choose from visual presets (Classic Grid, Cinematic List) during generation.
• Interactive navigation: Automatically wire directional navigation and page-turn actions (Next/Back) for generated nodes.

Workflow runtime

• Generation Heuristics (Backend): Add Rust-side logic to slice project entities (Chapters, Titles) into paginated groups based on target budgets.
• Scene Spawning (Frontend): Implement store actions to dynamically create MenuDocument objects and populate them with standard SceneNode variants.
• Data Binding: Establish a persistent link between generated nodes and source metadata to support safe regeneration.
• Pagination Mandate: Enforce a hard budget of 12-18 buttons per page to ensure technical compliance and UX legibility.

Documentation

• Spec update: Expand Spindle_Menu_System_Spec.md to define the automated generation meta-model.
• User guidance: Add documentation for 'Menu Sets' and pagination behaviour in the menu authoring guide.

Test plan

[ ] Regression: Verify that manually authored menus remain unaffected by the generation engine.
[ ] Pagination proof: Generate a Chapter Menu for a title with 30+ chapters — verify multiple pages are created.
[ ] Navigation integrity: Verify that 'Next' and 'Back' buttons correctly route between paginated scenes in the remote simulator.
[ ] Persistence: Verify that generated menu metadata round-trips through the Rust serializer without data loss.
[ ] Hardware limits: Verify that the generator prevents creation of menus exceeding 36 buttons (DVD limit).

🤖 Generated with Gemini CLI

[ScottMorris]

PR #24 Impact Assessment

The current PR (#24 – feat/menu-workspace-upgrade) has significant overlap with this issue but is not fully addressing all requirements. Here's the breakdown:

✅ Directly Addressed

• Menu workspace UI improvements — Extensive menu workspace refinement (canvas guides, inspector sections, left-rail toggles)
• Theme/visual preset selection — Font dropdown, style panels, visual integration work
• Scene spawning & data binding — Menu nodes with richer defaults and backend model updates
• Navigation controls — Return variant to PlaybackAction, navigation map with editor/map modes

⚠️ Partially/Indirectly Addressed

• Pagination engine — No explicit pagination commits visible; the issue requires hard budgets (12-18 buttons per page, max 36 buttons), but generation heuristics not evident in Rust
• Automated generation tools — Workspace refinements focus on authoring UI, but "one-click generation" tooling not apparent in commits
• Data binding for regeneration — Model updates exist, but no explicit regeneration-safety logic visible

❌ Not Yet Addressed

• Generation heuristics (Backend) — Rust-side logic to slice chapters/titles into paginated groups
• Hard pagination budget enforcement — 12-18 buttons per page validation
• Interactive navigation wiring — Auto-wiring of Next/Back buttons for generated menus
• Documentation — Spec expansion and user guidance for Menu Sets

Summary

PR #24 is a necessary foundation for this issue (~40-50% of scope) but critical missing pieces are the automated generation engine and pagination heuristics on the Rust side, plus the tooling to trigger generation from the UI.