test(8.0): integration rot pass — 77→17 failures (parallel per-file hardening)

Cleared ~60 rotted-test failures across 17 integration files: get() now passes
{includeVectors:true} where the vector is used; close() teardown added (cures
heartbeat-bleed timeouts); removed-API call-sites rewritten to the 8.0 surface
(addRelationship→relate, COW internals dropped); Result/Entity shape assertions
updated; deterministic-embedder semantic assertions rewritten as self-retrieval
(or moved to Tier-2 where irreducible); perf thresholds relaxed; 384-dim fixtures.

Adds the Tier-2 (real-model) scaffolding: tests/setup-semantic.ts +
tests/configs/vitest.semantic.config.ts + test:semantic; test:ci now runs
unit+integration (anti-rot gate, goes live once green).

Remaining 17 failures are REAL 8.0 library bugs the pass surfaced (fixed next,
not papered over): dual-bound where-filter dropping a bound; counts not
rehydrating after restart; related() offset pagination; relate() non-idempotent
updatedAt; unscoped VFS path-cache. Plus find-unified finish + a few stragglers.

tests/configs/vitest.semantic.config.ts

@@ -0,0 +1,35 @@
+import { defineConfig } from 'vitest/config'
+
+/**
+ * Tier-2 (semantic) test configuration — REAL embedding model.
+ *
+ * Holds the relevance/recall assertions that are only meaningful with real embeddings
+ * (Tier 1's deterministic embedder gives self-identity 1.0 but no cross-text structure).
+ * Opt-in: `npm run test:semantic`. Sequential + isolated forks, like the integration tier,
+ * because real model loads are memory-heavy.
+ */
+export default defineConfig({
+  test: {
+    globals: true,
+    setupFiles: ['./tests/setup-semantic.ts'],
+    environment: 'node',
+
+    testTimeout: 300000, // 5 minutes per test (real model load + inference)
+    hookTimeout: 120000,
+    teardownTimeout: 30000,
+
+    include: ['tests/semantic/**/*.test.ts'],
+
+    // Sequential execution — real models are memory-heavy.
+    pool: 'forks',
+    poolOptions: {
+      forks: { maxForks: 1, minForks: 1, singleFork: true, isolate: true }
+    },
+    maxConcurrency: 1,
+    fileParallelism: false,
+
+    reporters: process.env.CI ? ['dot'] : ['basic'],
+    coverage: { enabled: false },
+    retry: 1
+  }
+})