fix(core): correct WAAPI rediscovery seek baselines and preview reuse…

[func25]

… invalidation

What

Fix two related preview/runtime issues:

• correct WAAPI seek baselines for animations that appear after the composition has already advanced, including rediscovery paths
• stop reusing same-project preview servers when the embedded preview server build is stale

Why

Some WAAPI animations created mid-seek could inherit absolute composition time and collapse into the wrong visual state. In rediscovery paths, newly seen animations could also be double-counted after time had already advanced.

Preview server reuse only invalidated on project identity, and later only on runtime script identity. That was too narrow and could still reuse a stale same-project preview server even when other preview-server behavior had changed.

How

• track WAAPI baselines relative to the current seek/discovery point instead of always anchoring at zero
• add regression coverage for:
  • newly discovered WAAPI animations
  • rebased inherited absolute time
  • rediscovery after time has already advanced
  • replace preview reuse comparison based on runtime-only identity with a broader server build signature

Test plan

How was this tested?

• Unit tests added/updated
• Manual testing performed
• Documentation updated (if applicable)