fix T1+T4: wire rollback into pipeline; real Ollama telemetry in metrics

T1 (H7): casan-step.mjs now calls rollback-manager.sh checkpoint before
overwriting plan.md at attempt-2, writes tx-id to plan.checkpoint.txid
sidecar, and executes rollback on REJECTED verdict. rollback-transactions.jsonl
records a real cp restore command. Adversarial test: checkpoint exists,
real cp command recorded, plan hash matches pre-overwrite content.

T4 (H6): casan-harness.sh exports CASAN_STEP_NAME=$ACTION_NAME before
agent-metrics.sh so nested model calls (model-call.py) and the provider-
cost-lookup.py query share the same step label. metrics.jsonl now writes
cost_source=provider_telemetry instead of word_count_estimate when a real
Ollama call is made within the same step. Adversarial test: verified with
CASAN_STEP_NAME=t4-telemetry-test end-to-end.

adversarial-harness-tests.sh: 40 → 44 PASS / 0 FAIL (+3 T1, +1 T4)
security-gate.sh: PASS=10 FAIL=0 SKIP=0 (verified, local ornith:9b)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

AINative_OKR_CASAN5/.specify/logs/audit/tool-calls-head.sig

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