feat: plan 16 P1 complete (SEC-07 approval + SEC-10 agent identity)

- SEC-07 (M-08): real approval verification via approval-verify.sh in enforced mode
  (CASAN_PROFILE=prod / CASAN_APPROVAL_STRICT=1) for control-plane `set` (sensitive
  keys), kill-switch `clear`, and self-improve (inherits control-plane). A bare or
  forged approval string is now denied; dev mode stays backward-compatible.
- SEC-10 (M-05): non-spoofable agent identity. tool-registry-gate least-privilege no
  longer trusts CASAN_AGENT env in enforced mode (CASAN_IDENTITY_STRICT=1) — the
  caller must present a signed token (agent-identity-sign.sh) bound to agent id +
  run id, verified against agent-identities.registry. Blocks env spoofing + replay.

Verify: SEC+integrity gate 18/0, run-casan4 0-FAIL, adversarial 44/44 (H2 intact),
control-plane 9/0, h5-approval 12/0, c7-incident 15/0, self-improve 7/0, track-c 29/0.

Plan-16 P0 + P1 now complete; remaining: P2 (SEC-12/13/14/15/22..30).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

AINative_OKR_CASAN5/.specify/scripts/bash/ci-harness-gate.sh

@@ -102,6 +102,8 @@ run "phase-sec09-input-caps"     bash "$TESTS/phase-sec09-tests.sh"
 run "phase-sec19-atomic-store"   bash "$TESTS/phase-sec19-tests.sh"
 run "phase-sec20-toolchain"      bash "$TESTS/phase-sec20-tests.sh"
 run "phase-sec21-model-budget"   bash "$TESTS/phase-sec21-tests.sh"
+run "phase-sec07-approval"       bash "$TESTS/phase-sec07-tests.sh"
+run "phase-sec10-agent-identity" bash "$TESTS/phase-sec10-tests.sh"
 
 # ARCH-02: coverage cannot silently drop; ARCH-01: harness/policy cannot silently
 # drift. Both SKIP cleanly when no manifest is provisioned (non-strict dev/CI).