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/unit/test_vault_rw.py

@@ -0,0 +1,69 @@
+import json
+import pytest
+
+
+def test_set_and_get_key(tmp_pyra_home):
+    from pyra.vault.writer import set_key
+    from pyra.vault.reader import get_key
+
+    set_key("anthropic", "sk-ant-test-secret")
+    result = get_key("anthropic")
+    assert result == "sk-ant-test-secret"
+
+
+def test_key_not_in_config(tmp_pyra_home):
+    from pyra.vault.writer import set_key
+    from pyra.config.schema import ProviderConfig, PyraConfig
+    from pyra.config.manager import save_config, load_config
+
+    set_key("openai", "sk-supersecret")
+
+    cfg = PyraConfig(ai=ProviderConfig(provider_id="openai", model="gpt-4o"))
+    save_config(cfg)
+
+    config_text = (tmp_pyra_home / "config.yaml").read_text()
+    assert "sk-supersecret" not in config_text
+    assert "supersecret" not in config_text
+
+
+def test_keys_file_permissions(tmp_pyra_home):
+    import os
+    from pyra.vault.writer import set_key
+
+    set_key("deepseek", "test-key-value")
+    keys_file = tmp_pyra_home / "vault" / "secrets" / "api_keys.json"
+
+    if os.name != "nt":
+        mode = oct(keys_file.stat().st_mode)[-3:]
+        assert mode == "400", f"Expected 400, got {mode}"
+
+
+def test_multiple_providers(tmp_pyra_home):
+    from pyra.vault.writer import set_key
+    from pyra.vault.reader import get_key
+
+    set_key("anthropic", "key-1")
+    set_key("openai", "key-2")
+    set_key("gemini", "key-3")
+
+    assert get_key("anthropic") == "key-1"
+    assert get_key("openai") == "key-2"
+    assert get_key("gemini") == "key-3"
+
+
+def test_delete_key(tmp_pyra_home):
+    from pyra.vault.writer import set_key, delete_key
+    from pyra.vault.reader import get_key
+
+    set_key("anthropic", "to-be-deleted")
+    assert get_key("anthropic") == "to-be-deleted"
+
+    existed = delete_key("anthropic")
+    assert existed is True
+    assert get_key("anthropic") is None
+
+
+def test_get_missing_key_returns_none(tmp_pyra_home):
+    from pyra.vault.reader import get_key
+    result = get_key("nonexistent_provider")
+    assert result is None