Merge pull request #79 from RtlZeroMemory/reconciliation-hardening

Harden reconciliation coverage across keyed, unkeyed, mixed, composite and deep trees

Author: RtlZeroMemory

docs/dev/testing.md

@@ -12,6 +12,19 @@ The repo uses:
 - golden tests for drawlists/layout/routing where byte-level stability matters
 - fuzz-lite tests for binary parsers (bounded, never-throw)
 
+## Reconciliation Hardening Matrix
+
+Reconciliation edge-cases are covered by dedicated runtime suites:
+
+- `packages/core/src/runtime/__tests__/reconcile.keyed.test.ts`
+- `packages/core/src/runtime/__tests__/reconcile.unkeyed.test.ts`
+- `packages/core/src/runtime/__tests__/reconcile.mixed.test.ts`
+- `packages/core/src/runtime/__tests__/reconcile.composite.test.ts`
+- `packages/core/src/runtime/__tests__/reconcile.deep.test.ts`
+
+These suites lock deterministic behavior for keyed reorder/insert/remove, unkeyed grow/shrink,
+mixed keyed+unkeyed slots, `defineWidget` hook/state persistence, and deep-tree reconciliation.
+
 Related CI gates:
 
 - [Perf Regressions](./perf-regressions.md)