refactor: 분리되어 관리하고 있던 문서 시스템을 하나로 통일

docs/_templates/evidence/meta/evidence.json

@@ -0,0 +1,13 @@
+{
+  "id": "<evidence-id>",
+  "kind": "terminal|browser|query-plan|benchmark|other",
+  "sourceRevision": "<git revision or snapshot>",
+  "executedAt": "<ISO-8601>",
+  "command": "<command without secrets or null>",
+  "cwd": "<working directory or null>",
+  "exitCode": null,
+  "rawPath": "evidence/raw/<file>",
+  "presentationPath": "evidence/terminal|browser|svg/<file>",
+  "proves": "<bounded claim>",
+  "doesNotProve": "<important limitation>"
+}