feat: 添加结构化日志与审计

- tracing + tracing-subscriber，全局 --verbose/-v 与 RUST_LOG 控制
- 新增 audit_log 表，add/update/delete 成功后自动写入审计记录
- 新增 src/audit.rs，审计失败仅 warn 不中断主流程
- 更新 README/AGENTS.md，补充 verbose、audit_log 说明
- .vscode/tasks.json 增加 verbose/update/audit 测试任务

Made-with: Cursor

.vscode/tasks.json

@@ -25,12 +25,36 @@
       "command": "./target/debug/secrets help add",
       "dependsOn": "build"
     },
+    {
+      "label": "cli: help config",
+      "type": "shell",
+      "command": "./target/debug/secrets help config",
+      "dependsOn": "build"
+    },
+    {
+      "label": "cli: config path",
+      "type": "shell",
+      "command": "./target/debug/secrets config path",
+      "dependsOn": "build"
+    },
+    {
+      "label": "cli: config show",
+      "type": "shell",
+      "command": "./target/debug/secrets config show",
+      "dependsOn": "build"
+    },
     {
       "label": "test: search all",
       "type": "shell",
       "command": "./target/debug/secrets search",
       "dependsOn": "build"
     },
+    {
+      "label": "test: search all (verbose)",
+      "type": "shell",
+      "command": "./target/debug/secrets --verbose search",
+      "dependsOn": "build"
+    },
     {
       "label": "test: search by namespace (refining)",
       "type": "shell",
@@ -82,7 +106,7 @@
     {
       "label": "test: search with secrets revealed",
       "type": "shell",
-      "command": "./target/debug/secrets search -n refining --kind service --name gitea --show-secrets",
+      "command": "./target/debug/secrets search -n refining --kind service --show-secrets",
       "dependsOn": "build"
     },
     {
@@ -97,6 +121,24 @@
       "command": "echo '--- add ---' && ./target/debug/secrets add -n test --kind demo --name roundtrip-test --tag test -m foo=bar -s password=secret123 && echo '--- search ---' && ./target/debug/secrets search -n test --show-secrets && echo '--- delete ---' && ./target/debug/secrets delete -n test --kind demo --name roundtrip-test && echo '--- verify deleted ---' && ./target/debug/secrets search -n test",
       "dependsOn": "build"
     },
+    {
+      "label": "test: add + delete roundtrip (verbose)",
+      "type": "shell",
+      "command": "echo '--- add (verbose) ---' && ./target/debug/secrets --verbose add -n test --kind demo --name roundtrip-verbose --tag test -m foo=bar -s password=secret123 && echo '--- delete (verbose) ---' && ./target/debug/secrets --verbose delete -n test --kind demo --name roundtrip-verbose",
+      "dependsOn": "build"
+    },
+    {
+      "label": "test: update roundtrip",
+      "type": "shell",
+      "command": "echo '--- add ---' && ./target/debug/secrets add -n test --kind demo --name update-test --tag v1 -m env=staging && echo '--- update ---' && ./target/debug/secrets update -n test --kind demo --name update-test --add-tag v2 --remove-tag v1 -m env=production && echo '--- verify ---' && ./target/debug/secrets search -n test --kind demo && echo '--- cleanup ---' && ./target/debug/secrets delete -n test --kind demo --name update-test",
+      "dependsOn": "build"
+    },
+    {
+      "label": "test: audit log",
+      "type": "shell",
+      "command": "echo '--- add ---' && ./target/debug/secrets add -n test --kind demo --name audit-test -m foo=bar -s key=val && echo '--- update ---' && ./target/debug/secrets update -n test --kind demo --name audit-test -m foo=baz && echo '--- delete ---' && ./target/debug/secrets delete -n test --kind demo --name audit-test && echo '--- audit log (last 5) ---' && psql $DATABASE_URL -c \"SELECT action, namespace, kind, name, actor, detail, created_at FROM audit_log ORDER BY created_at DESC LIMIT 5;\"",
+      "dependsOn": "build"
+    },
     {
       "label": "test: add with file secret",
       "type": "shell",