feat: 配置加载 config（三 yaml + env 优先级 + 脱敏）

tests/fixtures/app.yaml

@@ -0,0 +1,7 @@
+server:
+  max_upload_mb: 10
+session:
+  sqlite_path: "C:/tmp/genesis.db"
+task_queue:
+  backend: memory
+  timeout_sec: 300

tests/fixtures/inference.yaml

@@ -0,0 +1,8 @@
+models:
+  primary:
+    provider: deepseek
+    name: deepseek-chat
+llm_calls:
+  max_context_tokens: 16000
+structured_output:
+  max_parse_retry: 3

tests/fixtures/rag.yaml

@@ -0,0 +1,9 @@
+embedding:
+  model: BAAI/bge-small-zh-v1.5
+vector_store:
+  adapter: chroma
+  qdrant:
+    url: http://qdrant:6333
+    api_key: ${QDRANT_API_KEY}
+retrieval:
+  rrf_k: 42

tests/test_config.py

@@ -0,0 +1,51 @@
+from pathlib import Path
+
+from genesis.config import Settings
+
+FIXTURES = Path(__file__).parent / "fixtures"
+
+
+def test_from_dir_maps_yaml_fields():
+    s = Settings.from_dir(FIXTURES)
+    assert s.app.server.max_upload_mb == 10
+    assert s.app.session["sqlite_path"] == "C:/tmp/genesis.db"
+    assert s.app.task_queue["timeout_sec"] == 300
+    assert s.inference.models.primary.name == "deepseek-chat"
+    assert s.inference.llm_calls.max_context_tokens == 16000
+    assert s.inference.structured_output.max_parse_retry == 3
+    assert s.rag.embedding.model == "BAAI/bge-small-zh-v1.5"
+    assert s.rag.retrieval.rrf_k == 42
+
+
+def test_defaults_when_dir_empty(tmp_path):
+    s = Settings.from_dir(tmp_path)
+    assert s.app.name == "genesis"
+    assert s.app.server.max_upload_mb == 100
+    assert s.app.task_queue["backend"] == "memory"
+    assert s.inference.models.primary.name == "deepseek-chat"
+    assert s.rag.embedding.model == "BAAI/bge-small-zh-v1.5"
+    assert s.rag.retrieval.rrf_k == 60
+
+
+def test_env_override_yaml(monkeypatch):
+    monkeypatch.setenv("GENESIS_APP__SERVER__MAX_UPLOAD_MB", "25")
+    s = Settings.from_dir(FIXTURES)
+    assert s.app.server.max_upload_mb == 25
+
+
+def test_env_create_missing_key(monkeypatch):
+    monkeypatch.setenv("GENESIS_RAG__RETRIEVAL__DEFAULT_TOP_K", "7")
+    s = Settings.from_dir(FIXTURES)
+    assert s.rag.retrieval.default_top_k == 7
+
+
+def test_env_placeholder_expansion(monkeypatch):
+    monkeypatch.setenv("QDRANT_API_KEY", "sk-test-xyz")
+    s = Settings.from_dir(FIXTURES)
+    assert s.rag.vector_store.qdrant.api_key == "sk-test-xyz"
+
+
+def test_redacted_hides_secrets():
+    s = Settings.from_dir(FIXTURES)
+    red = s.get_redacted()
+    assert red["rag"]["vector_store"]["qdrant"]["api_key"] == "***"