fix: resolve v5.7.0 deadlock by restoring storage layer separation (v5.7.1)

CRITICAL BUG FIX - v5.7.0 caused complete production failure

PROBLEM:
v5.7.0 introduced circular dependency deadlock during GraphAdjacencyIndex initialization:
  GraphAdjacencyIndex.rebuild()
  → storage.getVerbs()
  → getVerbsBySource_internal()
  → getGraphIndex() [NEW in v5.7.0]
  → [waiting for rebuild to complete]
  → DEADLOCK

SYMPTOMS (Production Impact):
- ALL imports hung at "Reading Data Structure" for 760+ seconds
- brain.add() operations took 12+ seconds per entity (50x slower)
- Zero entities imported successfully
- 100% of Workshop users unable to import files
- No errors thrown - infinite wait
- Forced immediate rollback to v5.6.3

ROOT CAUSE:
v5.7.0 modified storage internal methods (getVerbsBySource_internal,
getVerbsByTarget_internal) to use GraphAdjacencyIndex optimization,
creating tight coupling where storage depends on index AND index depends
on storage. This violated separation of concerns and created deadlock.

SOLUTION (Architectural Fix):
Reverted storage internals to v5.6.3 implementation (lines 2320-2444):
- Storage layer simple, no index dependencies ✅
- GraphAdjacencyIndex can safely call storage.getVerbs() to rebuild ✅
- No circular dependency possible ✅
- Proper layered architecture restored ✅

LAYERS (Correct Architecture):
  Layer 3 (Brainy/Queries): CAN use GraphAdjacencyIndex
  Layer 2 (GraphAdjacencyIndex): Uses storage.getVerbs() to rebuild
  Layer 1 (Storage Internals): NO GraphAdjacencyIndex calls

IMPACT:
- Slightly slower GraphAdjacencyIndex.rebuild() (one-time init cost)
- High-level queries still use optimized index
- Import performance unaffected (writes don't trigger init)
- NO breaking changes to public API

TESTING:
- Added 4 regression tests (tests/regression/v5.7.0-deadlock.test.ts)
- All 1146 existing tests pass ✅
- Import + relationships complete in <1 second (not 760+)
- No 12+ second delays per entity ✅

FILES CHANGED:
- src/storage/baseStorage.ts (reverted lines 2320-2444 to v5.6.3)
- tests/regression/v5.7.0-deadlock.test.ts (new regression tests)
- CHANGELOG.md (comprehensive v5.7.1 entry with upgrade instructions)

VERIFICATION:
Workshop team should upgrade immediately:
  npm install @soulcraft/brainy@5.7.1

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

tests/regression/v5.7.0-deadlock.test.ts

@@ -0,0 +1,159 @@
+import { describe, it, expect, beforeEach } from 'vitest'
+import { Brainy } from '../../src/brainy.js'
+import { VerbType } from '../../src/types/graphTypes.js'
+
+/**
+ * Regression test for v5.7.0 deadlock bug
+ *
+ * BUG DESCRIPTION:
+ * v5.7.0 introduced a circular dependency deadlock during GraphAdjacencyIndex initialization:
+ * - GraphAdjacencyIndex.rebuild() calls storage.getVerbs()
+ * - storage.getVerbsBySource_internal() calls getGraphIndex()
+ * - getGraphIndex() is waiting for rebuild() to complete
+ * - DEADLOCK: Each waits for the other
+ *
+ * SYMPTOMS:
+ * - ALL imports hang at "Reading Data Structure" stage
+ * - brain.add() operations take 12+ seconds per entity (50x slower)
+ * - No errors thrown - infinite wait
+ * - Process continues (heartbeats) but makes no progress
+ *
+ * FIX (v5.7.1):
+ * Reverted storage internals (getVerbsBySource_internal, getVerbsByTarget_internal)
+ * to v5.6.3 implementation - no getGraphIndex() calls from storage layer.
+ *
+ * TEST STRATEGY:
+ * 1. Create entities with relationships (triggers GraphAdjacencyIndex lazy init)
+ * 2. Force rebuild by accessing graph operations
+ * 3. Verify completes in <1 second (not 760+ seconds)
+ */
+describe('v5.7.0 Deadlock Regression', () => {
+  let brain: Brainy
+
+  beforeEach(async () => {
+    brain = new Brainy({ storage: { type: 'memory' } })
+    await brain.init()
+  })
+
+  it('should not deadlock during GraphAdjacencyIndex rebuild with existing verbs', async () => {
+    // Create 10 entities
+    const entities = []
+    for (let i = 0; i < 10; i++) {
+      const id = await brain.add({
+        data: `Entity ${i}`,
+        type: 'thing',
+        metadata: { index: i }
+      })
+      entities.push(id)
+    }
+
+    // Create relationships between them (triggers GraphAdjacencyIndex)
+    for (let i = 0; i < 9; i++) {
+      await brain.relate({
+        from: entities[i],
+        to: entities[i + 1],
+        type: VerbType.RelatedTo
+      })
+    }
+
+    // This should complete in <1 second (not hang forever)
+    const start = Date.now()
+
+    // Force GraphAdjacencyIndex usage by querying relationships
+    const relations = await brain.getRelations({ from: entities[0] })
+
+    const elapsed = Date.now() - start
+
+    // Verify no deadlock
+    expect(elapsed).toBeLessThan(1000)
+    expect(relations.length).toBeGreaterThan(0)
+  })
+
+  it('should handle imports without 12+ second delays per entity', async () => {
+    // Simulate import workflow (like Workshop Excel import)
+    const start = Date.now()
+
+    // Import 5 entities with relationships
+    const importedEntities = []
+    for (let i = 0; i < 5; i++) {
+      const id = await brain.add({
+        data: `Imported Entity ${i}`,
+        type: 'person',
+        metadata: {
+          importId: 'test-import-001',
+          sourceRow: i
+        }
+      })
+      importedEntities.push(id)
+    }
+
+    // Add relationships
+    for (let i = 0; i < 4; i++) {
+      await brain.relate({
+        from: importedEntities[i],
+        to: importedEntities[i + 1],
+        type: VerbType.Knows
+      })
+    }
+
+    const elapsed = Date.now() - start
+
+    // In v5.7.0, this took 12+ seconds per entity (60+ seconds total)
+    // In v5.7.1, should complete in <5 seconds for 5 entities
+    expect(elapsed).toBeLessThan(5000)
+
+    // Verify all entities were created
+    for (const id of importedEntities) {
+      const entity = await brain.get(id)
+      expect(entity).toBeDefined()
+    }
+  })
+
+  it('should allow GraphAdjacencyIndex rebuild without circular dependency', async () => {
+    // Create initial data
+    const entity1 = await brain.add({ data: 'Node A', type: 'thing' })
+    const entity2 = await brain.add({ data: 'Node B', type: 'thing' })
+    const entity3 = await brain.add({ data: 'Node C', type: 'thing' })
+
+    await brain.relate({ from: entity1, to: entity2, type: VerbType.RelatedTo })
+    await brain.relate({ from: entity2, to: entity3, type: VerbType.RelatedTo })
+
+    // Accessing storage internals should not cause deadlock
+    // GraphAdjacencyIndex initialization should complete successfully
+    const start = Date.now()
+
+    // This would trigger initialization if not already done
+    const relations = await brain.getRelations({ from: entity1 })
+
+    const elapsed = Date.now() - start
+
+    // Should be fast (no deadlock, no 12s delays)
+    expect(elapsed).toBeLessThan(500)
+    expect(relations).toHaveLength(1)
+    expect(relations[0].to).toBe(entity2)
+  })
+
+  it('should handle multiple concurrent adds without deadlock', async () => {
+    // Simulate concurrent entity creation (like batch import)
+    const start = Date.now()
+
+    const promises = []
+    for (let i = 0; i < 10; i++) {
+      promises.push(
+        brain.add({
+          data: `Concurrent Entity ${i}`,
+          type: 'thing',
+          metadata: { batch: true, index: i }
+        })
+      )
+    }
+
+    const ids = await Promise.all(promises)
+    const elapsed = Date.now() - start
+
+    // Should complete quickly (no 12s per entity delays)
+    // 10 entities should take <2 seconds, not 120+ seconds
+    expect(elapsed).toBeLessThan(2000)
+    expect(ids).toHaveLength(10)
+  })
+})