fix(issue-9,14): sanitize herdr server env and confirm accepted prompt delivery

- Drop per-session agent runtime markers (CLAUDECODE, CLAUDE_CODE_CHILD_SESSION,
  CLAUDE_CODE_SESSION_ID, Claude Code messaging/bridge/pid markers, and the
  agy/hermes/grok/opencode session ids) from the environment lib.sh's shim hands
  to a bootstrapped `herdr --session <name> server`; user configuration such as
  CLAUDE_PROJECT_DIR still inherits
- Add MAM_NO_AUTOSTART=1 so query-only callers never bootstrap a server as a side
  effect; status.sh and reconcile.sh export it, and the shim's `ls` reports a down
  server as "no server running" so reconcile keeps herdr_confirmed instead of
  freezing drift detection for every server
- send_keys_safe: treat `timeout` / `agent_prompt_stalled` from `agent prompt
  --wait` as an accepted submission and confirm delivery for SKS_DELIVERY_GRACE_S
  (default 15 s) via agent_status working, a busy token the pane did not show
  before, or the pane moving on from its pre-submit snapshot; no signal at all
  still fails closed (rc 4). Codex under herdr 0.9.0 never reports `working`, so
  every delivered prompt was closed as agent_blocked and its later
  started/completed events refused
- delegate wrapper: before closing an unconfirmed inject as agent_blocked, honour
  the registry's own acknowledgement for MAM_INJECT_ACK_GRACE_S (default 10 s)
- Switch T1-7's failure trigger to transport_error (timeout now means accepted);
  add test_issue9_server_env.py (5 cases) and test_issue14_delivery_ack.py (7)
- Verified live: a freshly bootstrapped multi-agent-mux server carries no markers
  and the claude panes save transcripts again; codex job d04ebcb5 had its
  started/completed accepted with no agent_blocked

Closes #9
Closes #14

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VCgu9Fa9iT7TbJUSzdq4Ff

tests/test_issue6_fail_closed.py

@@ -259,12 +259,15 @@ def test_t1_7_custom_registry_dir_inject_failure(tmp_path, mock_herdr):
     # Set up mock herdr with an agent, but prompt will fail
     state_file = Path(mock_herdr)
     state = json.loads(state_file.read_text())
+    # A transport-level RPC failure is a definite inject failure. (`timeout` is
+    # not: since Issue #14 it means herdr accepted the submission and only its
+    # status watch timed out, which send_keys_safe then confirms via the pane.)
     state["agents"]["fail-agent"] = {
         "agent": "claude",
         "agent_status": "idle",
-        "prompt_wait_result": "timeout",  # will fail prompt
+        "prompt_wait_result": "transport_error",  # will fail prompt
     }
-    state["prompt_wait_result"] = "timeout"
+    state["prompt_wait_result"] = "transport_error"
     state_file.write_text(json.dumps(state, indent=2))
 
     res = _run_wrapper(
@@ -278,7 +281,7 @@ def test_t1_7_custom_registry_dir_inject_failure(tmp_path, mock_herdr):
             "--timeout", "15",
             "--idle-timeout", "10",
         ],
-        env={"SKS_BUSY_TIMEOUT": "1", "SKS_IDLE_TIMEOUT_MS": "500"},
+        env={"SKS_BUSY_TIMEOUT": "1", "SKS_IDLE_TIMEOUT_MS": "500", "MAM_INJECT_ACK_GRACE_S": "1"},
         cwd=tmp_path,
         timeout=60,
     )