Slate v2 Core Perf Batch

Goal

Land the next real core-performance cuts after the normalization win:

• transaction bootstrap cost
• transaction read cost
• lazy traversal for nodes(...)
• lazy traversal for positions(...)
• hot current-node read cost on insert

Rules

• no fake performance wins by narrowing behavior
• no scope reduction
• one real measured improvement minimum before considering stop
• keep regression evidence fresh

Phases

• Phase 0: Grounding
  • context snapshot
  • known hot seams
• Phase 1: Kill the biggest structural cost
  • outer transaction full-tree clone
  • or transaction read full-tree clone
• Phase 2: Kill traversal materialization waste
  • attempted Editor.nodes(...)
  • attempted Editor.positions(...)
  • regressing fast paths reverted after measurement
• Phase 3: Kill hot current-node cloning on insert
• Phase 4: Re-measure core huge-doc and observation benches
• Phase 5: Regression proof
  • targeted contract tests
  • full slate package tests
  • build
  • typecheck
  • diagnostics

Current Evidence

• explicit normalization cliff is no longer the first problem:
  • adjacent-text 134.20ms -> 3.08ms
  • inline flatten 1779.73ms -> 10.36ms
  • observation path in the same bench 109.95ms -> 78.01ms
• core huge-document typing improved but is still very red:
  • final direct fast-path rerun:
    • start-block 370.97ms -> 0.62ms
    • middle-block 368.58ms -> 0.65ms
• core observation improved on the clean stable branch versus the original read:
  • final direct fast-path rerun:
    • editor.children.length 940.18ms -> 1.34ms
    • Editor.nodes(...) 1275.18ms -> 98.41ms
    • Editor.positions(...) 1013.11ms -> 61.08ms
• attempted nodes(...) / positions(...) fast paths regressed badly and were reverted
• final kept wins:
  • dirty-path-scoped non-explicit normalization for simple text/property ops
  • cached cloned children per transaction mutation version
  • raw current-node helper for hot internal reads
  • direct top-level insert_text / remove_text fast path that bypasses full transaction bootstrap and full snapshot rebuild when paths stay stable