fix(tier2): top-level permission allowlist - sandbox paths now enforced

Regression: a Tier 2 session was denied access to
C:\\projects\\manual_slop_tier2\\scripts\\run_tests_batched.py
with 'Allowed base directories are: gencpp, manual_slop'. The
tier2-autonomous agent had a correct permission.read allowlist, but
the top-level permission block (inherited from the main repo's
opencode.json via 'git clone') had no read/write keys, and OpenCode
uses the top-level for the default agent path. The agent's
permission.read was merged but apparently not enforced for the
default-agent access check.

Fix:
1. Add a top-level 'permission' block to
   conductor/tier2/opencode.json.fragment with:
   - permission.edit: 'deny' (default agents locked down)
   - permission.read: deny *, allow sandbox clone + app-data dirs
   - permission.write: same
   - permission.bash: deny *, allowlist of read-only git commands +
     uv run python scripts/{run_tests_batched.py,tier2/*} + basic
     shell commands. git push/checkout/restore/reset remain denied.

2. Update setup_tier2_clone.ps1 to also patch the top-level
   'permission' block (was only merging the tier2-autonomous agent
   block). The script preserves the user's mcp, model, instructions,
   watcher, and plugin settings from the inherited opencode.json.

3. Update test_tier2_slash_command_spec.py:
   - Rename test_command_fetches_origin_main -> ..._master (we
     changed the slash command on 2026-06-17).
   - Add test_config_fragment_has_top_level_permission to assert
     the new top-level permission block has the right deny-all +
     allowlist shape.

The tier2-autonomous agent's permission block is unchanged; it
overrides the top-level for that agent's tool calls.

tests/test_tier2_slash_command_spec.py

@@ -42,9 +42,9 @@ def test_command_uses_git_switch_not_checkout() -> None:
  assert all("checkout" not in line for line in shell_lines), f"protocol uses git checkout: {shell_lines}"
 
 
-def test_command_fetches_origin_main() -> None:
+def test_command_fetches_origin_master() -> None:
  content = COMMAND_PATH.read_text(encoding="utf-8")
- assert "git fetch origin main" in content
+ assert "git fetch origin master" in content
 
 
 def test_command_initializes_failcount_state() -> None:
@@ -87,3 +87,26 @@ def test_config_fragment_valid_json() -> None:
  assert "git checkout*" in perms["bash"]
  assert "git restore*" in perms["bash"]
  assert "git reset*" in perms["bash"]
+
+
+def test_config_fragment_has_top_level_permission() -> None:
+ """Top-level permission.read/write MUST allow the sandbox dirs (added
+ 2026-06-17 after the bug where the agent's permission.read was not
+ enforced for the default agent, leading to ACCESS DENIED on
+ manual_slop_tier2 paths)."""
+ data = json.loads(CONFIG_PATH.read_text(encoding="utf-8"))
+ assert "permission" in data
+ top = data["permission"]
+ assert "read" in top, "top-level permission.read is required"
+ assert top["read"].get("*") == "deny", "top-level permission.read MUST deny *"
+ assert top["read"].get("C:\\projects\\manual_slop_tier2\\**") == "allow", "sandbox clone path must be allowlisted"
+ assert "write" in top
+ assert top["write"].get("*") == "deny"
+ assert top["write"].get("C:\\projects\\manual_slop_tier2\\**") == "allow"
+ assert "bash" in top
+ assert top["bash"].get("*") == "deny", "top-level bash MUST deny * (default agents are locked down)"
+ assert top["bash"].get("git status*") == "allow", "read-only git commands must be in the allowlist"
+ assert top["bash"].get("git push*") == "deny"
+ assert top["bash"].get("git checkout*") == "deny"
+ assert top["bash"].get("git restore*") == "deny"
+ assert top["bash"].get("git reset*") == "deny"