feat(plugins): add source-aware evidence and recording timelines

examples/plugins/evidence-demo/plugin.json

@@ -0,0 +1,24 @@
+{
+  "schema_version": 2,
+  "id": "evidence-demo",
+  "name": "文件证据示例",
+  "version": "1.0.0",
+  "description": "开发模板：写入任务专属文本文件并返回校验回执。",
+  "artemis_version": ">=2.0.0,<3.0.0",
+  "platforms": ["win32", "linux", "darwin"],
+  "architectures": ["amd64", "arm64"],
+  "server": {"command": "${config.python}", "args": ["${plugin_dir}/server.py"]},
+  "config": {"python": {"label": "含 MCP 依赖的 Python", "default": "python"}},
+  "skill": "SKILL.md",
+  "targets": ["mixed", "computer"],
+  "resources": [],
+  "capabilities": {
+    "kind": "file",
+    "recording": "none",
+    "required_tools": ["write_note"],
+    "tools": {"write_note": {
+      "effect": "write", "observation": false, "idempotent": false,
+      "cancellation": "unknown", "evidence": ["text", "file"]
+    }}
+  }
+}