ci: fix false positives in link checker (file:// + SoundCloud)

Author: DavidKRK

.lychee.toml

@@ -5,10 +5,14 @@
 # - mailto: links are not real HTTP URLs
 # - soundcloud.com: blocks automated link checkers with 403 (anti-bot protection)
 # - formspree.io: form POST endpoints return 405 for GET requests (expected behavior)
+# - file://: local filesystem paths used by GitHub Actions runner (not real web links)
+# - mysql.com: returns 403 for bots
+# - scripts.sil.org: known redirect issues
 exclude = [
   "^mailto:",
   "soundcloud\\.com",
   "formspree\\.io",
   "mysql\\.com",
-  "scripts\\.sil\\.org"
+  "scripts\\.sil\\.org",
+  "^file://"
 ]