feat(mcp): enhance form UX with default apps and JSON formatter

- Enable all apps (Claude, Codex, Gemini) by default when adding MCP servers
- Improve config label with clearer wording: "Full JSON configuration or use [Config Wizard]"
- Add JSON format button to beautify configuration with 2-space indentation
- Update tests to reflect new default behavior
- Clean up redundant explicit prop passing

This provides a more streamlined experience by enabling all apps out of the box
and making it easier to format JSON configurations.

src/i18n/locales/zh.json

@@ -469,6 +469,8 @@
       "docsPlaceholder": "https://example.com/docs",
       "additionalInfo": "附加信息",
       "jsonConfig": "JSON 配置",
+      "jsonConfigOrPrefix": "完整的 JSON 配置或者使用",
+      "tomlConfigOrPrefix": "完整的 TOML 配置或者使用",
       "jsonPlaceholder": "{\n  \"type\": \"stdio\",\n  \"command\": \"uvx\",\n  \"args\": [\"mcp-server-fetch\"]\n}",
       "tomlConfig": "TOML 配置",
       "tomlPlaceholder": "type = \"stdio\"\ncommand = \"uvx\"\nargs = [\"mcp-server-fetch\"]",