Fix coomer: bogus video formats on image posts, and its CDN reachability in check.py

- coomer.rs: only emit a `formats` entry for actual video extensions.
  Image-only posts (very common - many creators post photos, not just
  videos) were getting a `formats[0]` pointing at a static jpg/png, which
  a player would try and fail to stream as video; the preview URL already
  covers showing the image.
- coomer.rs tests: fix stale fixtures that baked a `/data/` prefix into
  `file.path`, which doesn't match the real API's path shape (the code
  prepends `/data/` itself) and was doubling it into `/data/data/...`.
  This was masking the formats bug above until the fixture was corrected.
- check.py: coomer.st/data/... 302s to a load-balanced nN.coomer.st CDN
  node; every node tested (n1/n2/n3) is a hard connect-timeout from this
  sandbox's egress while coomer.st itself is a normal 200 - the same
  IP-reputation-style CDN block already documented for ripnsfw's
  doodstream/lulustream edges. Added `.coomer.st` to the CF-protected
  suffix allowlist, and made the url/thumb checks follow redirects before
  testing it (previously only the format-url check did).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QTqf6orbHZ9rFFpVpcgzcR

check.py

@@ -127,6 +127,12 @@ _CF_PROTECTED_SUFFIXES = (
     # lulustream's signed HLS edge (reached via ripnsfw's /proxy/lulustream/...).
     # Returns 403/522 to datacenter IPs regardless of UA/TLS impersonation.
     ".tnmr.org",
+    # coomer's file CDN: coomer.st/data/... 302s to a load-balanced nN.coomer.st
+    # edge node (n1, n2, n3, n4, ...); every node is a hard connect-timeout from
+    # this sandbox's egress (verified: n1/n2/n3 all time out while coomer.st
+    # itself is a normal 200) — an IP-reputation-style CDN block, not a code
+    # defect. The leading dot means bare `coomer.st` itself is unaffected.
+    ".coomer.st",
 )
 
 
@@ -325,7 +331,8 @@ def check_video(video: dict, channel_id: str, results: Results, run_ytdlp: bool)
     else:
         ok, code = http_ok(vurl)
         if not ok:
-            if _is_cf_protected(vurl):
+            resolved_vurl = follow_proxy_redirect(vurl)
+            if _is_cf_protected(vurl) or _is_cf_protected(resolved_vurl):
                 results.warn(channel_id, f"{label}: url unreachable HTTP={code} (CF-protected host, expected): {vurl}")
             else:
                 results.err(channel_id, f"{label}: url unreachable HTTP={code}: {vurl}")
@@ -336,7 +343,8 @@ def check_video(video: dict, channel_id: str, results: Results, run_ytdlp: bool)
     if thumb:
         ok, code = http_ok(thumb)
         if not ok:
-            if _is_cf_protected(thumb):
+            resolved_thumb = follow_proxy_redirect(thumb)
+            if _is_cf_protected(thumb) or _is_cf_protected(resolved_thumb):
                 results.warn(channel_id, f"{label}: thumb unreachable HTTP={code} (CF-protected host, expected): {thumb}")
             else:
                 results.err(channel_id, f"{label}: thumb unreachable HTTP={code}: {thumb}")