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

.agents/skills/multi-agent-mux-status/scripts/status.sh

@@ -7,6 +7,11 @@
 # Usage: bash status.sh [--json]
 set -euo pipefail
 
+# ISSUE-9: a status query must not bootstrap a herdr server as a side effect.
+# With this set, the lib.sh shim reports a session whose isolated server is
+# down as dead instead of starting a headless daemon just to answer.
+export MAM_NO_AUTOSTART=1
+
 source "$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)/lib.sh"
 
 RECONCILE="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)/multi-agent-mux-monitor/scripts/reconcile.sh"