fix: harden engine, enrich failure diagnostics, close adoption gaps

- P0: CLI verify now honors  test budget with seeded multi-sample
- P0: Observe sampling enforced via Math.random() gate in hook-validator
- P1: Remove misleading undici-mock-agent isolation option
- P1: Qualify reuses shared discoverRouteDetails() with warnings
- P1: Chaos/scenario config exposed via preset schema
- P1: README/docs limitations updated to current state
- P2: Nested response annotations prefer 2xx deterministically
- P2: --changed documented as heuristic in verify.md

- Add observe sink tests (sampling 0/1, sink failure non-interference)
- Add verify runs regression tests (scale, determinism, variants)
- Add configured-scenario qualify test (independent of OAuth fixture)
- Add coverageBreakdown to qualify artifacts (per-gate route coverage)
- Add production-style observe example with real sink in docs/observe.md
- Add nightly/staging vs PR gating guidance to docs/qualify.md

- Enrich VerifyFailure with formula-aware diagnostics:
  status:201 => 'HTTP 200', body field checks => actual values
- Remove stale observe CLI activation message
- Document outbound mocks as process-global in getting-started.md
- Refresh APOPHIS_ADOPTION_AUDIT.md with current state

903 tests pass, build clean, typecheck clean.

apophis.config.ts

@@ -0,0 +1,41 @@
+/**
+ * APOPHIS configuration
+ * Generated by `apophis init`
+ */
+
+import type { ApophisConfig } from "@apophis/fastify";
+
+const config: ApophisConfig = {
+  mode: "verify",
+  profile: "llm-check",
+  profiles: {
+    "llm-check": {
+      name: "llm-check",
+      mode: "verify",
+      preset: "llm-safe",
+      routes: []
+    }
+  },
+  presets: {
+    "llm-safe": {
+      name: "llm-safe",
+      timeout: 3000,
+      parallel: false,
+      chaos: false,
+      observe: false
+    }
+  },
+  environments: {
+    local: {
+      name: "local",
+      allowVerify: true,
+      allowObserve: false,
+      allowQualify: false,
+      allowChaos: false,
+      allowBlocking: false,
+      requireSink: false
+    }
+  }
+};
+
+export default config;