github: use lychee for docs link checking

Author: minijackson

.github/workflows/docs-linkcheck.yml

@@ -1,6 +1,7 @@
 name: "Docs linkcheck"
 
 on:
+  pull_request:
   workflow_dispatch:
   schedule:
     - cron: '0 7 * * 1'  # At 07:00 on Monday
@@ -23,4 +24,6 @@ jobs:
           persist-credentials: false
       - uses: nixbuild/nix-quick-install-action@2c9db80fb984ceb1bcaa77cdda3fdf8cfba92035 # v34
       - name: "Check docs links"
-        run: nix run --print-build-logs '.#ci-scripts/docs-linkcheck'
+        run: nix run --print-build-logs '.#checks.x86_64-linux.docs-linkcheck.online'
+        env:
+          GITHUB_TOKEN: ${{ github.token }}

pkgs/ci-scripts/by-name/docs-linkcheck/package.nix

@@ -1,4 +1,28 @@
 # Non-NixOS tests
 { pkgs, ... }:
 {
+  docs-linkcheck = pkgs.testers.lycheeLinkCheck {
+    site = "${pkgs.epnix.docs}/share/doc/epnix/html";
+    remap = let
+      current-version = pkgs.epnixLib.versions.current;
+      current-branch = if current-version == "dev" then "master" else current-version;
+    in {
+      "^https://epics-extensions.github.io/EPNix/${current-version}/" =
+        "file://${pkgs.epnix.docs}/share/doc/epnix/html/";
+
+      "^https://github.com/epics-extensions/(epn|EPN)ix/blob/${current-branch}/([^?]+)(\\?.+)?$" = "file://${self}/\\$2";
+      "^https://github.com/epics-extensions/(epn|EPN)ix/tree/${current-branch}/([^?]+)(\\?.+)?$" = "file://${self}/\\$2";
+      "^https://github.com/epics-extensions/(epn|EPN)ix/edit/${current-branch}/([^?]+)(\\?.+)?$" = "file://${self}/\\$2";
+    };
+    extraConfig = {
+      max_concurrency = 5;
+      max_retries = 5;
+      retry_wait_time = 3;
+
+      exclude_all_private = true;
+      extensions = [ "html" ];
+      require_https = true;
+      hosts."matrix.to".include_fragments = false;
+    };
+  };
 }