fix: address external audit — criticals 1-5 + mediums

Critical 1 (approval forgery): audit_log is now hash-chained
(prev_hash/entry_hash, verify_audit_chain); executor approve REQUIRES a
BIP-340 signature over sha256(cayce-ops:approve:<id>) when
CAYCE_OPS_OPERATOR_PUBKEY is set; deploy/roles.sql ships least-privilege
per-daemon DB roles.

Critical 2 (threading dead): sends create real OUTBOUND rows (own
Message-ID, In-Reply-To -> inbound); inbound message_id never overwritten;
maild compose adds the first-contact path; _match_proposal falls back to
inbound chains.

Critical 3 (duplicate sends): per-message transactions in send path —
SMTP failure on message N no longer resurrects 1..N-1; failures audited
(send_failed) and the row stays queued.

Critical 4 (classifier): negated approvals (cannot accept / not approved /
not accepting) classify REJECTION at 0.95 before the bare-keyword rule;
LLM prompt braces escaped (.format no longer KeyError into silent fallback).

Critical 5 (systemd): every daemon has a run subcommand
(maild run = poll+send, publisher run = publish-due, monitor run = build);
deploy README documents the separate daily publisher plan timer.

Mediums: approved_hash binds drafts/captions to the approved text (edited
text refuses to send/publish until re-approved); risk_score renamed
match_score (migration 0002) and auto-approve orders HIGHEST relevance
first; compose binds postgres to 127.0.0.1; IMAP marks \\Seen only after
commit (fetch returns (num, raw), mark post-commit); disabled channels are
terminal (ContentStatus.SKIPPED) and publish failures burn a bounded
attempt budget before abandonment; make hooks installs the pre-push gate.

tests: 12 new — 56 total, all green; ruff 0 findings; gitleaks clean.

tests/test_models.py

@@ -90,3 +90,23 @@ def test_mail_and_content_and_runs(sess):
     assert m.id and c.id and r.id
     assert m.draft_status == "drafted"
     assert c.status == "draft"
+
+
+def test_audit_chain_and_verification(sess):
+    from cayceops.models import verify_audit_chain
+
+    p = Proposal(kind="other", title="chain")
+    sess.add(p)
+    sess.flush()
+    for i in range(3):
+        audit(sess, actor=f"actor-{i}", action="step", proposal_id=p.id, detail={"i": i})
+    sess.flush()
+
+    ok, broken = verify_audit_chain(sess)
+    assert ok and broken is None
+
+    # tamper with one entry -> chain breaks at that id
+    first = sess.query(AuditEntry).order_by(AuditEntry.id).first()
+    first.actor = "tampered"
+    ok, broken = verify_audit_chain(sess)
+    assert not ok and broken == first.id