fix(agents): harden shell adapter bridge and address double-check review feedback

- create_session.sh: add explicit case fallback for delegate_agent (R1)
- lib_py.agents: add spawn-spec, resume-spec, exit-key argv CLI subcommands (R2)
- resume_session.sh, stop_session.sh: replace python string interpolation with safe argv subcommands (R2)
- stop_session.sh: dynamically iterate adapter.identity_cache_fields (R3)
- verify_session.py, workspace_uuid.py: remove dead imports (R9/N4)
- tests/test_a4_adapter_contract.py: add CLI bridge subcommand, clean-env PYTHONPATH safety, and fallback contract tests (R12/N1)
- SKILL.md, docs, logs: synchronize IMPROVEMENTS.md, LOG.md, and resolve_session_id wording (R8/R10/R11)
- promote verified peer review reports for cline (e7b9812b) and claude (31730364)

.agents/skills/multi-agent-mux-resume/scripts/resume_session.sh

@@ -36,6 +36,10 @@ done
 
 [ -n "$WORKSPACE" ] || { echo "ERROR: --workspace required" >&2; exit 2; }
 [ -n "$AGENT" ]    || { echo "ERROR: --agent required" >&2; exit 2; }
+case "$AGENT" in
+  claude|agy|hermes|cline) ;;
+  *) echo "ERROR: unsupported agent: $AGENT" >&2; exit 2 ;;
+esac
 [ -n "$SESSION_NAME" ] || { echo "ERROR: --session required" >&2; exit 2; }
 
 # 1. Resolve the session id
@@ -81,7 +85,7 @@ if [ "$(uname)" = "Darwin" ] && [ -f "$RESOLVED_BIN" ]; then
 fi
 
 # Determine CMD_FULL via adapter
-CMD_FULL="$("$(_delegate_py_bin)" -c "from lib_py.agents.registry import get_adapter; from lib_py.agents.base import DiscoveryContext; a = get_adapter('$AGENT'); ctx = DiscoveryContext('$WORKSPACE', '$AGENT'); mat = a.verify_artifact('$UUID', ctx) if a else False; print(a.resume_spec('$RESOLVED_BIN', '$UUID', mat) if a else '')" 2>/dev/null || true)"
+CMD_FULL="$("$(_delegate_py_bin)" -m lib_py.agents resume-spec "$AGENT" "$RESOLVED_BIN" "$UUID" "$WORKSPACE" 2>/dev/null || true)"
 if [ -z "$CMD_FULL" ]; then
   case "$AGENT" in
     claude) CMD_FULL="${RESOLVED_BIN} --dangerously-skip-permissions -r $UUID" ;;