test: comprehensive test suite

Unit tests:
- test_security_boundaries.py: vault block, vault lock sentinel
- test_security_injection.py: all 4 injection categories, case-insensitive
- test_vault_rw.py: roundtrip, file permissions (chmod 400), no key in config
- test_config.py: schema roundtrip, no api_key field, chmod 600 on config.yaml
- test_memory_reader.py: list, read, sandboxing, context loading
- test_memory_writer.py: write, append, index update, traversal blocked, chmod 600
- test_providers.py: required fields, unique IDs, litellm prefix format
- test_renderer.py: key redaction for sk-ant-, sk-, AIza patterns

Security tests:
- test_vault_ai_isolation.py: 7 traversal patterns blocked via memory read/write
- test_path_traversal.py: 20+ traversal patterns — all rejected for read and write
- test_prompt_injection.py: 21-item corpus + 5 clean texts (no false positives)

Integration tests:
- test_lmstudio.py: live call to localhost:1234, streaming, full stack session,
  injection scan on real output (skips if LM Studio not running)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/security/test_vault_ai_isolation.py

@@ -0,0 +1,47 @@
+"""
+Verify that vault paths cannot be reached via the memory reader API
+regardless of what string the AI might supply.
+"""
+import pytest
+from pyra.security.boundaries import VaultAccessError
+
+
+TRAVERSAL_NAMES = [
+    "../../../../vault/secrets/api_keys.json",
+    "../vault/secrets/api_keys.json",
+    "context/../../vault/secrets/api_keys.json",
+    "user/../../../vault/secrets/api_keys.json",
+    "%2e%2e/vault/secrets/api_keys.json",
+    "/root/anywhere",
+    "~/secret",
+]
+
+
+@pytest.mark.parametrize("name", TRAVERSAL_NAMES)
+def test_memory_read_cannot_reach_vault(tmp_pyra_home, name):
+    from pyra.memory.reader import read_memory
+    with pytest.raises((VaultAccessError, PermissionError, FileNotFoundError)):
+        read_memory(name)
+
+
+def test_memory_write_cannot_reach_vault(tmp_pyra_home):
+    from pyra.memory.writer import write_memory
+    with pytest.raises((VaultAccessError, PermissionError, ValueError)):
+        write_memory("../../vault/secrets/api_keys.json", "evil content")
+
+
+def test_direct_vault_read_blocked(tmp_pyra_home):
+    """assert_safe_path must block the vault path directly."""
+    from pyra.security.boundaries import assert_safe_path, VAULT_PATH
+    with pytest.raises(VaultAccessError):
+        assert_safe_path(VAULT_PATH / "secrets" / "api_keys.json")
+
+
+def test_vault_lock_sentinel_required(tmp_pyra_home):
+    """Deleting .vault_lock causes bootstrap to raise PyraSecurityError."""
+    from pyra.security.boundaries import PyraSecurityError
+    lock = tmp_pyra_home / "vault" / ".vault_lock"
+    lock.unlink()
+    with pytest.raises(PyraSecurityError):
+        from pyra.security.boundaries import check_vault_lock
+        check_vault_lock()