feat(zen): v3.29.0 - complete Solid.js algorithm absorption

SOLID.JS CORE ALGORITHM IMPLEMENTATION:
1. ✅ track() optimization - incremental source tracking
2. ✅ Proper STATE_CHECK - recursive check all sources first
3. ✅ Global clock system - _time instead of epoch
4. ✅ Incremental source updates - only update changed portion
5. ✅ Error clearing at update start (recovery)
6. ✅ No global updateCount - acyclic graph guarantee
7. ✅ Proper context management - save/restore observer/owner

CRITICAL FIXES:
- Fixed effect double-fire: FLAG_PENDING now cleared AFTER update()
- Fixed effect re-scheduling: isExecutingSelf branch bypasses FLAG_PENDING
- Fixed STATE_CHECK propagation: removed premature CLEAN setting
- Fixed deep reactivity: removed global updateCount infinite loop detector

This enables deep reactivity patterns (100-layer chains, diamond, fanout)
that were failing with 0 ops/sec in benchmarks.

Author: shtse8