Add unified setup script (configure.js) merging deploy + config wizard

Single-file Node.js CLI that orchestrates the full setup lifecycle:
- Interactive env var configuration with validation and smart defaults
- Postgres provisioning via Docker Compose with readiness polling
- Schema initialization (psql with docker exec fallback)
- npm dependency installation with 120s timeout
- Optional SQLite-to-Postgres data migration with retry logic
- Frontend build with smart skip on reconfiguration

Includes 84 tests: 50 property-based (fast-check) covering 19 correctness
properties, and 34 integration tests for filesystem and parsing flows.

backend/__tests__/config-wizard-buildskip.property.test.js

@@ -0,0 +1,121 @@
+/**
+ * Property-Based Tests: Config Wizard Frontend Build Skip Logic
+ *
+ * Feature: config-wizard
+ *
+ * Tests the shouldSkipFrontendBuild function from `configure.js`.
+ *
+ * Validates: Requirements 14.4, 14.5
+ */
+
+const fc = require('fast-check');
+const { shouldSkipFrontendBuild } = require('../../configure.js');
+
+// ─────────────────────────────────────────────────────────────────────────────
+// Helpers
+// ─────────────────────────────────────────────────────────────────────────────
+
+/** Generate a REACT_APP_* key name */
+const reactAppKeyArb = fc.stringMatching(/^REACT_APP_[A-Z][A-Z0-9_]{0,15}$/)
+  .filter(k => k.length > 10);
+
+/** Generate a non-empty env value */
+const envValueArb = fc.string({ minLength: 1, maxLength: 50 })
+  .filter(s => s.trim().length > 0 && !s.includes('\n'));
+
+// ─────────────────────────────────────────────────────────────────────────────
+// Property 19: Frontend build skip determination
+// ─────────────────────────────────────────────────────────────────────────────
+
+describe('Property 19: Frontend build skip determination', () => {
+  /**
+   * **Validates: Requirements 14.4, 14.5**
+   *
+   * shouldSkipFrontendBuild returns true iff all REACT_APP_* keys have identical
+   * values in old and new maps and old map is non-null.
+   */
+
+  test('when old map is null, always returns false', () => {
+    fc.assert(
+      fc.property(
+        fc.array(fc.tuple(reactAppKeyArb, envValueArb), { minLength: 1, maxLength: 5 }),
+        (entries) => {
+          const newMap = new Map(entries);
+          return shouldSkipFrontendBuild(null, newMap) === false;
+        }
+      ),
+      { numRuns: 100 }
+    );
+  });
+
+  test('when old and new have identical REACT_APP_* values, returns true', () => {
+    fc.assert(
+      fc.property(
+        fc.array(fc.tuple(reactAppKeyArb, envValueArb), { minLength: 1, maxLength: 5 }),
+        (entries) => {
+          // Deduplicate keys by using a Map
+          const deduped = [...new Map(entries).entries()];
+          const oldMap = new Map(deduped);
+          const newMap = new Map(deduped);
+          return shouldSkipFrontendBuild(oldMap, newMap) === true;
+        }
+      ),
+      { numRuns: 100 }
+    );
+  });
+
+  test('when any REACT_APP_* value differs, returns false', () => {
+    fc.assert(
+      fc.property(
+        fc.array(fc.tuple(reactAppKeyArb, envValueArb), { minLength: 1, maxLength: 5 }),
+        envValueArb,
+        (entries, differentValue) => {
+          // Deduplicate keys
+          const deduped = [...new Map(entries).entries()];
+          if (deduped.length === 0) return true; // skip trivial case
+
+          const oldMap = new Map(deduped);
+          const newMap = new Map(deduped);
+
+          // Change one value in the new map to be different
+          const keyToChange = deduped[0][0];
+          const originalValue = deduped[0][1];
+          // Ensure the new value is actually different
+          const newValue = differentValue === originalValue
+            ? differentValue + '_changed'
+            : differentValue;
+          newMap.set(keyToChange, newValue);
+
+          return shouldSkipFrontendBuild(oldMap, newMap) === false;
+        }
+      ),
+      { numRuns: 100 }
+    );
+  });
+
+  test('when new map has additional REACT_APP_* keys not in old, returns false', () => {
+    fc.assert(
+      fc.property(
+        fc.array(fc.tuple(reactAppKeyArb, envValueArb), { minLength: 1, maxLength: 3 }),
+        reactAppKeyArb,
+        envValueArb,
+        (entries, extraKey, extraValue) => {
+          // Deduplicate keys
+          const deduped = [...new Map(entries).entries()];
+          const oldMap = new Map(deduped);
+          const newMap = new Map(deduped);
+
+          // Add an extra key to new that doesn't exist in old
+          // Ensure the extra key is not already in the map
+          const uniqueExtraKey = deduped.some(([k]) => k === extraKey)
+            ? extraKey + '_EXTRA'
+            : extraKey;
+          newMap.set(uniqueExtraKey, extraValue);
+
+          return shouldSkipFrontendBuild(oldMap, newMap) === false;
+        }
+      ),
+      { numRuns: 100 }
+    );
+  });
+});