fix(herdr): ensure unique agent name via sha1 truncation and align mock errors

- Replace legacy s[:16]-s[-15:] truncation with 8-char SHA-1 hash suffix in sanitize.py and lib.sh to prevent workspace name collisions
- Align mock Herdr error messages in tests/conftest.py to real Herdr 0.8.0 output format
- Add missing required/invalid_agent_name to early abort regex in lib.sh
- Remove legacy heuristics in lib.sh has-session and unify mock agent lookups
- Add unit tests in tests/test_sanitize_and_mock_errors.py (256/256 passed)

tests/test_sanitize_and_mock_errors.py

@@ -0,0 +1,84 @@
+import subprocess
+import hashlib
+import json
+import sys
+import pytest
+from lib_py.agents.sanitize import sanitize_herdr_agent_name
+
+def test_sanitize_sibling_workspace_non_collision():
+    """
+    Verifies that sibling workspaces with identical prefix and suffix
+    do NOT collapse into the same 32-character sanitized herdr agent name.
+    """
+    workspaces = [
+        "canary-projects-educative-export-tools-creator-claude",
+        "canary-projects-getting-started-a2a-creator-claude",
+        "canary-projects-multi-agent-mux-creator-claude",
+        "canary-projects-pu-riverpod-cookbook-creator-claude",
+    ]
+    sanitized = [sanitize_herdr_agent_name(w) for w in workspaces]
+    
+    # 1. All lengths <= 32
+    for s in sanitized:
+        assert len(s) <= 32, f"Length exceeds 32: {s}"
+        assert len(s) == 32, f"Expected 32 chars for long names: {s}"
+    
+    # 2. All names are unique (0 collisions)
+    assert len(set(sanitized)) == len(workspaces), f"Collisions detected: {sanitized}"
+
+def test_sanitize_bash_python_parity(mam_sandbox):
+    """
+    Verifies that bash _sanitize_herdr_agent_name and Python sanitize_herdr_agent_name
+    produce byte-for-byte identical output across various edge cases.
+    """
+    test_cases = [
+        "canary-projects-multi-agent-mux-creator-claude",
+        "canary-projects-educative-export-tools-creator-claude",
+        "canary-projects-getting-started-a2a-creator-claude",
+        "canary-projects-pu-riverpod-cookbook-creator-claude",
+        "short-name",
+        "UPPER_CASE_123.dots",
+        "123_starts_digit",
+        "_underscore_leading",
+        "",
+        "exact-32-chars-long-name-1234567",
+        "exact-33-chars-long-name-12345678",
+    ]
+    lib_path = mam_sandbox / ".agents" / "skills" / "lib.sh"
+    
+    for case in test_cases:
+        py_res = sanitize_herdr_agent_name(case)
+        cmd = f"""
+        source {lib_path}
+        _sanitize_herdr_agent_name "{case}"
+        """
+        bash_res = subprocess.check_output(["bash", "-c", cmd]).decode().strip()
+        assert py_res == bash_res, f"Mismatch for '{case}': Python={py_res} vs Bash={bash_res}"
+
+def test_mock_herdr_error_formatting_and_abort(mock_herdr, mock_agents):
+    """
+    Verifies that mock herdr error output matches real Herdr 0.8.0 format
+    and triggers lib.sh early abort regex.
+    """
+    import re
+    abort_regex = re.compile(r"^usage:|unknown option|unknown flag|missing required|invalid_agent_name|^error:", re.IGNORECASE)
+    mock_bin = str(mock_agents / "herdr")
+    
+    # 1. Unknown flag
+    res_unknown = subprocess.run([mock_bin, "agent", "start", "testagent", "--kind", "claude", "--pane", "w1:p1", "--env", "FOO=BAR"], capture_output=True, text=True)
+    assert res_unknown.returncode != 0
+    assert abort_regex.search(res_unknown.stderr) is not None, f"Stderr did not match abort regex: {res_unknown.stderr}"
+    assert "unknown option: --env" in res_unknown.stderr
+
+    # 2. Missing required --pane
+    res_missing = subprocess.run([mock_bin, "agent", "start", "testagent", "--kind", "claude"], capture_output=True, text=True)
+    assert res_missing.returncode != 0
+    assert abort_regex.search(res_missing.stderr) is not None, f"Stderr did not match abort regex: {res_missing.stderr}"
+    assert "missing required --pane" in res_missing.stderr
+
+    # 3. Invalid agent name
+    res_badname = subprocess.run([mock_bin, "agent", "start", "BAD_NAME", "--kind", "claude", "--pane", "w1:p1"], capture_output=True, text=True)
+    assert res_badname.returncode != 0
+    assert abort_regex.search(res_badname.stderr) is not None, f"Stderr did not match abort regex: {res_badname.stderr}"
+    assert "invalid_agent_name" in res_badname.stderr
+