fix(deploy): clear stale self-deploy markers on rollback; document env

Re-deploy after a FAILED prod deploy wedged the task on `deploy`: the
sentinel markers (approve-requested/initiated/result) are keyed by the
stable work_item_id, so after the БАГ-8 rollback (deploy -> development)
and a developer fix, Phase B's idempotency-guard saw a STALE `initiated`
and became a no-op — the detached hook never re-launched and the
finalizer was never enqueued. Add self_deploy.clear_state (never-raise,
idempotent) and call it on the check_deploy_status FAILED rollback and at
the start of Phase A, so every fresh prod-deploy pass starts clean.

Also document the new ORCH_SELF_DEPLOY_* / ORCH_DEPLOY_* descriptors in
the canonical .env.example (CLAUDE.md rule #8, ТЗ §2.6), modelled on the
ORCH-043 merge-gate block (placeholders only, secrets not committed).

Contracts untouched: STAGE_TRANSITIONS, QG_CHECKS, _parse_deploy_status,
БАГ-8, merge-gate.

Refs: ORCH-036
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tests/test_deploy_hook_mapping.py

@@ -11,6 +11,7 @@ import os
 os.environ.setdefault("ORCH_PLANE_API_TOKEN", "test-token")
 os.environ.setdefault("ORCH_GITEA_TOKEN", "test-token")
 
+from src import self_deploy  # noqa: E402
 from src.self_deploy import map_exit_code_to_status, build_deploy_log  # noqa: E402
 
 
@@ -45,3 +46,21 @@ def test_deploy_log_frontmatter_carries_status():
     body_fail = build_deploy_log("ORCH-036", 2, "FAILED")
     assert "deploy_status: FAILED" in body_fail
     assert "hook_exit_code: 2" in body_fail
+
+
+def test_clear_state_removes_all_markers_and_is_idempotent(monkeypatch, tmp_path):
+    """clear_state wipes the whole work-item state dir (all sentinels) and treats a
+    missing dir as success, so a re-deploy after rollback starts from a clean slate."""
+    monkeypatch.setattr(self_deploy.settings, "repos_dir", str(tmp_path))
+    repo, wi = "orchestrator", "ORCH-036"
+    self_deploy.write_marker(repo, wi, self_deploy.APPROVE_REQUESTED, "t")
+    self_deploy.write_marker(repo, wi, self_deploy.INITIATED, "t")
+    self_deploy.write_marker(repo, wi, self_deploy.RESULT, "1")
+    assert self_deploy.has_marker(repo, wi, self_deploy.INITIATED) is True
+
+    assert self_deploy.clear_state(repo, wi) is True
+    assert self_deploy.has_marker(repo, wi, self_deploy.APPROVE_REQUESTED) is False
+    assert self_deploy.has_marker(repo, wi, self_deploy.INITIATED) is False
+    assert self_deploy.has_marker(repo, wi, self_deploy.RESULT) is False
+    # Idempotent: clearing an already-absent dir is still success (never raises).
+    assert self_deploy.clear_state(repo, wi) is True