Implement property-based reactivity engine and stabilize layout rendering

[piraz]

Objective:

Modernize the Faz Core by replacing the current verbose reactivity model with a streamlined property-based engine and fixing the layout "blink"
issue during component initialization.

Technical Requirements:

1. Reactivity Engine:
   • Create a standalone utility bindReactive(target, key, value) that maps JS properties to SolidJS signals.
   • Refactor FazElement, FazFormElement, and FazPaginator to use this new engine.
   • Ensure type safety using keyof and Partial during initialization.
2. Layout Stability:
   • Initialize components with display: contents to prevent layout jumps.
   • Ensure the rendering process remains synchronous relative to the microtask queue to avoid "un-retrofitted" states being painted.
3. Cleanup:
   • Remove legacy Accessor/Setter tuples and redundant helper methods (like addReactive).
   • Standardize child collection logic to be independent of the loading state.

Definition of Done:

• Unit tests for the new reactivity engine passed.
• All existing core components (Form, Paginator) updated and tests passing.
• Proof of Concept (POC) verified: no layout blink and correct Bootstrap rendering.