feat: CI verification pipeline and structural conformance gates

- Add scripts/check-structural.js: counts production as any, empty catch,
  and ?? 0 patterns; fails CI if counts exceed committed baseline
- Add scripts/.structural-baseline.json: committed baseline (101 as any,
  17 empty catch, 62 ?? 0); use --fix-baseline to ratchet down
- Add scripts/ci-verify.sh: ordered pipeline (build → typecheck → lint →
  structural → unit tests → E2E) with pass/fail summary
- Add npm scripts: test:structural, test:structural:fix, ci:verify
- Add cache-staleness conformance test: verifies WORLD_CACHE_SCHEMA_VERSION
  is prefixed to all cache keys for auto-invalidation on schema changes
- Cache test suite grows from 141 → 142 passes

scripts/check-structural.js

@@ -0,0 +1,109 @@
+/**
+ * Structural conformance gate.
+ *
+ * Counts production-source code-smells and compares against committed baselines.
+ * Nonzero exit code = a baseline was violated.  The script does NOT alter
+ * files; it only audits and reports.
+ *
+ * Usage: node scripts/check-structural.js [--fix-baseline]
+ */
+
+import { readFileSync, writeFileSync } from 'fs'
+import { fileURLToPath } from 'url'
+import glob from 'glob'
+import path from 'path'
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url))
+const ROOT = path.resolve(__dirname, '..')
+const BASELINE_PATH = path.join(ROOT, 'scripts', '.structural-baseline.json')
+
+const PACKAGE_DIRS = glob.sync('packages/*', { cwd: ROOT, absolute: true })
+  .filter(d => !d.match(/(imhotep-fixtures|imhotep-bench|imhotep-cli)$/))
+
+function srcFiles(pkgDir) {
+  return glob.sync('src/**/*.ts', { cwd: pkgDir, absolute: true })
+    .filter(f => !f.endsWith('.test.ts') && !f.endsWith('.d.ts'))
+}
+
+function countPattern(files, pattern, excludeComment = false) {
+  let count = 0
+  const locations = []
+  for (const f of files) {
+    const lines = readFileSync(f, 'utf8').split('\n')
+    for (let i = 0; i < lines.length; i++) {
+      const line = lines[i]
+      if (excludeComment && line.trim().startsWith('//')) continue
+      const matches = line.match(pattern)
+      if (matches) {
+        count += matches.length
+        locations.push(`${path.relative(ROOT, f)}:${i + 1}`)
+      }
+    }
+  }
+  return { count, locations }
+}
+
+const allFiles = PACKAGE_DIRS.flatMap(d => srcFiles(d))
+const pkgNames = PACKAGE_DIRS.map(d => path.basename(d))
+
+const violations = {
+  asAny: countPattern(allFiles, /\bas any\b/g, true),
+  emptyCatch: countPattern(allFiles, /\bcatch\s*\{/),
+  nullishZero: countPattern(allFiles, /\?\?\s*0(?![.\d])/, true),
+}
+
+const baseline = (() => {
+  try { return JSON.parse(readFileSync(BASELINE_PATH, 'utf8')) }
+  catch { return {} }
+})()
+
+const results = {
+  timestamp: new Date().toISOString(),
+  packages: pkgNames,
+  violations,
+  baseline,
+}
+
+const errors = []
+
+for (const [key, current] of Object.entries(violations)) {
+  const allowed = baseline[key] ?? 0
+  const delta = current.count - allowed
+  const status = delta <= 0 ? 'PASS' : 'FAIL'
+  const msg = `  ${key.padEnd(18)} current=${String(current.count).padStart(3)}  baseline=${String(allowed).padStart(3)}  delta=${String(delta).padStart(4)}  ${status}`
+  console.log(msg)
+  if (status === 'FAIL') {
+    errors.push(`${key} (${current.count} > baseline ${allowed})`)
+    console.log(`    New locations:`)
+    for (const loc of current.locations.slice(0, 10)) {
+      console.log(`      ${loc}`)
+    }
+    if (current.locations.length > 10) {
+      console.log(`      ... and ${current.locations.length - 10} more`)
+    }
+  }
+}
+
+const fixBaseline = process.argv.includes('--fix-baseline')
+if (fixBaseline) {
+  const newBaseline = {}
+  for (const [key, v] of Object.entries(violations)) {
+    newBaseline[key] = v.count
+  }
+  writeFileSync(BASELINE_PATH, JSON.stringify(newBaseline, null, 2) + '\n')
+  console.log(`\n  Baseline written to ${path.relative(ROOT, BASELINE_PATH)}`)
+  console.log('Structural gate PASSED (baseline updated)')
+  process.exit(0)
+}
+
+writeFileSync(BASELINE_PATH, JSON.stringify(baseline, null, 2) + '\n')
+
+if (errors.length > 0) {
+  console.error(`\nStructural gate FAILED (${errors.length} violation(s)):`)
+  for (const e of errors) console.error(`  - ${e}`)
+  console.error(`\nIf these are legitimate, update the baseline with:`)
+  console.error(`  node scripts/check-structural.js --fix-baseline`)
+  process.exit(1)
+} else {
+  console.log('\nStructural gate PASSED')
+}