feat(h6): AgentOps hardening — live alerting, provider-API reconcile, hosted dashboard, window breaker (79→80)

Close the three gaps the scoring report itself flagged for H6 plus V15,
each as a real MVP + fail-able adversarial test (same pattern that lifted H5):

- D1 alert-dispatch.sh: alerts POST to a real HTTP webhook (severity routing,
  dedup window, retry) + dead-letter queue with redelivery; fail-loud in strict.
  Wired into agent-metrics.sh so a failing step pages live end-to-end.
- D2 provider-usage-fetch.sh + telemetry-reconcile.sh: pull usage from a provider
  usage HTTP API (all-or-nothing schema gate, fail-loud) + reconcile local vs
  provider ground truth — token under-reporting/hidden runs => TELEMETRY_DISCREPANCY.
- D3 dashboard-serve.sh + dashboard-server.py: serve the dashboard over HTTP with
  a stale-aware /healthz probe (fresh=200 ok, telemetry silent-death=503 stale).
- D4 circuit-breaker-check.sh: sliding-window failure-rate breaker (V15) — interleaved
  successes no longer evade the consecutive-failure breaker (CIRCUIT_OPEN_WINDOW).

New suite phase-h6-agentops-tests.sh: 20/20, all live against local HTTP endpoints
(webhook sink, mock provider API, dashboard server) — deterministic, no model needed.

Also fix sign-policy-bundle.sh key-sync invariant: the local-fallback branch only
exported policy-public.pem when generating a NEW key, so a Vault-DOWN run after a
Vault-signed run verified a local-key signature against the Vault pubkey (RSA padding
error, run-casan4 died mid-suite). Now always re-exports the pubkey before signing —
same fix class as tool-audit-lib.sh / governance-check.sh.

Full battery re-run sequentially: 175/175 PASS, 0 FAIL across 8 suites
(KMS SKIP this run — Vault down; validated live 2026-07-04). Docs synced:
scoring-run-report (H6 79→80, no harness below 80, 155→175), CASAN_HARDENING_STATUS
(Phase 5 D1–D4), Plan-07, submission README, and run-hardening.sh (H6+ scenes HO1–HO4).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

AINative_OKR_CASAN5/.specify/scripts/bash/sign-policy-bundle.sh

@@ -78,8 +78,11 @@ if [[ "$MODE" == "sign" ]]; then
     # ── Fallback: local key file (dev / no Vault) ─────────────────────────────
     if [[ ! -f "$PRIVATE_KEY" ]]; then
       openssl genrsa -out "$PRIVATE_KEY" 2048 >/dev/null 2>&1
-      openssl rsa -in "$PRIVATE_KEY" -pubout -out "$PUBLIC_KEY" >/dev/null 2>&1
     fi
+    # Key-sync invariant: the on-disk public key must ALWAYS match the key that
+    # signs (a prior Vault-signed run leaves the Vault pubkey here — verifying
+    # a local-key signature against it would fail with an RSA padding error).
+    openssl rsa -in "$PRIVATE_KEY" -pubout -out "$PUBLIC_KEY" >/dev/null 2>&1
     openssl dgst -sha256 -sign "$PRIVATE_KEY" -out "$SIGNATURE" "$MANIFEST"
     echo "POLICY_BUNDLE_SIGNED manifest=$MANIFEST signature=$SIGNATURE public_key=$PUBLIC_KEY key_backend=local-file"
   fi