ci(links): fix the stale lychee config key that kept the check disabled

Re-arming check-links surfaced why it was commented out in the first
place: lychee rejects the config outright — `follow_redirects` is not a
recognized key in the version the action pins, so the job died before
checking a single link. Replaced with `max_redirects` (lychee follows
redirects by default; this caps the chain).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: os-zhuang

lychee.toml

@@ -14,8 +14,8 @@ timeout = 30
 # Retry failed requests
 max_retries = 2
 
-# Follow redirects
-follow_redirects = true
+# Follow redirects (lychee follows by default; this caps the chain)
+max_redirects = 5
 
 # Check anchors/fragments in links
 include_fragments = false