feat(link): add external link guard feature support (#729)

* feat(external-link-guard): add native redirect mode and improve external-link guard UX

* fix(external-link-guard): remove redirect_url and clarify scope/new_tab_policy docs

* i18n(external-link-guard): localize guard texts across non-English locales

* feat(config)!: migrate `site.Params.externalIcon` to `site.Params.link.external_icon`

* refactor: implement regular and card link rendering

* feat(link-guard): implement link redirection page with copy and confirm functionality

* revert

* feat: implement link guard dialog for external links

---------

Co-authored-by: Cell <1024@lruihao.cn>

apps/test/content/posts/link-test.md

@@ -0,0 +1,88 @@
+---
+title: Link Rendering Test
+date: 2026-04-10T11:40:06+08:00
+collections:
+  - Tests
+categories:
+  - Markdown
+tags:
+  - Link
+---
+
+
+This post validates link rendering paths in FixIt, including Markdown render hook and link shortcode modes.
+
+<!--more-->
+
+## Markdown Render Hook (Regular Link)
+
+These links are rendered by `layouts/_markup/render-link.html` and should always produce regular links.
+
+- Internal relative link: [Task list test](/test/units/task-list-test/)
+- Internal anchor link: [Jump to Card Link section](#card-link-shortcode)
+- Absolute same-site link: [Test site home](http://demo.fixit.lruihao.cn/test/)
+- External HTTP link: [FixIt Repository](https://github.com/hugo-fixit/FixIt)
+- Mail link: [Email test](mailto:test@example.com)
+- JavaScript link: [JavaScript test](javascript:void(0))
+- Tel link: [Phone test](tel:+1234567890)
+- File link: [File test](file:///path/to/file.txt)
+- Data link: [Data URI test](data:text/plain;base64,SGVsbG8sIFdvcmxkIQ==)
+
+### Title Attribute (Markdown)
+
+[External link with title](https://example.com "Example Title")
+
+## Link Shortcode (Regular)
+
+### Named parameters
+
+{{< link href="https://github.com/hugo-fixit/FixIt" content="GitHub via shortcode" title="GitHub title" >}}
+
+{{< link href="/test/units/codeblock-test/" content="Internal shortcode link" class="shortcode-link-test" >}}
+
+{{< link href="https://example.com" content="Custom rel + no noreferrer" rel="ugc" noreferrer=false >}}
+
+{{< link href="/images/fixit.svg" content="Download local file" download="fixit.svg" >}}
+
+### Positional parameters
+
+{{< link "https://example.org" "Positional regular link" "Positional title" >}}
+
+## Card Link Shortcode
+
+### Basic card
+
+{{< link href="https://fixit.lruihao.cn" content="FixIt Documentation" card=true >}}
+
+### Card with custom icon class
+
+{{< link href="https://github.com/hugo-fixit/FixIt" content="FixIt on GitHub" card=true card-icon="fa-brands fa-github" >}}
+
+### Card with custom image icon
+
+{{< link href="https://gohugo.io" content="Hugo Official Site" card=true card-icon="/test/images/hugo.min.svg" >}}
+
+### Card with download state
+
+{{< link href="/images/fixit.svg" content="Download as card" card=true download="fixit.svg" >}}
+
+### Positional card parameters
+
+{{< link "https://example.com" "Positional card link" "" true "fa-solid fa-link" >}}
+
+## Edge Cases
+
+- URL with query string:
+  [Search query test](https://example.com/search?q=fixit&lang=en)
+- URL with fragment:
+  [Fragment test](https://example.com/docs#installation)
+- Long URL display (card meta should trim protocol automatically):
+  {{< link href="https://example.com/a/very/long/path/for/testing/card/url/display?foo=bar&baz=qux" content="Long URL card" card=true >}}
+
+## Manual Verification Checklist
+
+- Regular Markdown external links include external behavior and icon policy.
+- Internal links are not treated as external.
+- Shortcode card links render `.card-link` structure and card meta URL.
+- `download` shows download icon/state in both regular and card modes.
+- `noreferrer=false` removes `noopener noreferrer` from generated rel values.

apps/test/hugo.toml

@@ -49,3 +49,7 @@ avatar = "https://lruihao.cn/images/avatar.jpg"
 
 [params.mermaid]
 zenuml = "https://cdn.jsdelivr.net/npm/@mermaid-js/mermaid-zenuml/dist/mermaid-zenuml.esm.min.mjs"
+
+[params.dev]
+enable = true
+debug = true