feat: user-scoped history/delete/rollback, dashboard & login UI, ignore *.pem

- Filter history/rollback/delete by user_id in secrets-core
- MCP tools/web pass user context; dashboard refresh; favicon static
- .gitignore *.pem; vscode tasks tweaks
- clippy: collapse else-if in rollback latest-history branch

Made-with: Cursor

.vscode/tasks.json

@@ -1,23 +1,19 @@
 {
   "version": "2.0.0",
   "tasks": [
-    {
-      "label": "build",
-      "type": "shell",
-      "command": "cargo build --workspace --locked",
-      "group": { "kind": "build", "isDefault": true }
-    },
     {
       "label": "mcp: build",
       "type": "shell",
       "command": "cargo build --locked -p secrets-mcp",
-      "group": "build"
+      "group": "build",
+      "options": {
+        "envFile": "${workspaceFolder}/.env"
+      }
     },
     {
       "label": "mcp: run",
       "type": "shell",
       "command": "cargo run --locked -p secrets-mcp",
-      "dependsOn": "mcp: build",
       "options": {
         "envFile": "${workspaceFolder}/.env"
       }