Block Runner 0.9.9

Block Runner 0.9.9 catches malformed synced-pattern references before their inline content can be silently discarded.

• Reject nested blocks or HTML inside core/block references during validation, conversion and assembly. Failed fix operations preserve the original input.
• Explain shared pattern definitions, named instance overrides and explicit detachment in the agent guide.
• Add native Tabs assembly and WordPress editor/frontend regression coverage for persistence, independent instances and keyboard behaviour.
• Add development compatibility checks for generated blocks across WordPress 7.1, 7.1.2 and WordPress 7.1.2 with Gutenberg 24.0.0, and clarify the boundaries of that proof.
• Correct Accordion's first WordPress release to 6.9.

Thanks @roborourke for the concrete before/after example in #123 that exposed the validation gap. The guard and guidance are in #124.

This remains a pre-1.0 release. The optional model benchmark is unscored, and compatibility checks apply to the tested fixtures rather than every theme or plugin combination.

Full changelog: v0.9.8...v0.9.9