fix(auth): send X-Agent-Token + X-Agent-Team from all agent->API call sites

The prior fix (6ed4e139) covered the flow/do MCP servers but missed four
other agent->orchestrator call sites that built the header dict by hand
and omitted X-Agent-Token and/or X-Agent-Team. With ROBOCO_AGENT_AUTH_REQUIRED
armed on the NAS, every one 401s:

- agent_sdk/server.py: the session-end post-mortem flush
  (/api/journals/me/entries), A2A persistence + offline fallback
  (/api/a2a/*), and the stopped-without-transition auto-substitute
  (/api/tasks/auto-substitute) — all sent only X-Agent-ID/Role, so each
  401'd 'Missing X-Agent-Token'. Add a shared _agent_headers() helper
  (mirroring flow_server._build_headers) and route all four through it.
- agent_sdk/secretary_driver.py: _headers() sent the token but not the
  team, so the HMAC gate 401'd with signature mismatch (secretary is
  board-team; token signed with team='board', verified with team='').
  Add the team header.
- mcp/git_readonly.py: the read-only git MCP sent only X-Agent-ID/Role
  — no token, no team — so /api/git/* 401'd once auth was armed. Convert
  the static _HEADERS to a _headers() helper with team + token.
- runtime/orchestrator.py: the cell-PM auto-submit self-API call acted
  as a PM with a hand-built {X-Agent-ID, X-Agent-Role} dict — no token,
  no team — 401ing under auth-required. Add _agent_api_headers(uuid,
  role) mirroring _system_api_headers, and use it.

Tests: _agent_headers round-trip (token + team, team-omitted when None),
_agent_api_headers carries a signed PM token + team.

tests/unit/agent_sdk/test_agent_headers.py

@@ -0,0 +1,51 @@
+"""The SDK server's direct orchestrator calls must carry the agent HMAC
+token + team, or the API's ``ROBOCO_AGENT_AUTH_REQUIRED`` gate 401s with
+"Missing X-Agent-Token" — regression: the session-end post-mortem flush
+(``/api/journals/me/entries``), A2A persistence/fallback, and
+auto-substitute call all built the header dict by hand and omitted both,
+latent until auth was armed on the NAS deploy.
+"""
+
+from __future__ import annotations
+
+import importlib
+from typing import TYPE_CHECKING
+
+import roboco.agent_sdk.server as srv
+
+if TYPE_CHECKING:
+    import pytest
+
+
+def test_agent_headers_carries_token_and_team(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    be_dev_1 = "00000000-0000-0000-0001-000000000001"  # role=developer, team=backend
+    monkeypatch.setenv("ROBOCO_AGENT_ID", be_dev_1)
+    monkeypatch.setenv("ROBOCO_AGENT_ROLE", "developer")
+    monkeypatch.setenv("ROBOCO_AGENT_TOKEN", "test-hmac-token")
+    importlib.reload(srv)
+
+    headers = srv._agent_headers()
+
+    assert headers["X-Agent-ID"] == be_dev_1
+    assert headers["X-Agent-Role"] == "developer"
+    assert headers["X-Agent-Team"] == "backend"
+    assert headers["X-Agent-Token"] == "test-hmac-token"
+
+
+def test_agent_headers_omits_team_when_none(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    # A team-less agent (the `system` sentinel) confirms the team header is
+    # omitted, not sent empty — so the middleware passes "" and matches a
+    # token signed with team="".
+    monkeypatch.setenv("ROBOCO_AGENT_ID", "00000000-0000-0000-0000-000000000000")
+    monkeypatch.setenv("ROBOCO_AGENT_ROLE", "system")
+    monkeypatch.setenv("ROBOCO_AGENT_TOKEN", "test-hmac-token")
+    importlib.reload(srv)
+
+    headers = srv._agent_headers()
+
+    assert "X-Agent-Team" not in headers
+    assert headers["X-Agent-Token"] == "test-hmac-token"