feat(latest): poll comix through the browser sidecar (#98)

comix.to began answering plain-TLS fetches with a Cloudflare JavaScript
challenge on 2026-08-12, so every poll got a 403 interstitial and its cover
host static.comix.to is gated the same way. comix joins kagane and novelfull
as a browser Site: one registry entry, no plain-TLS fallback, and cover bytes
routed through the browser's image path behind a fully pinned URL pattern.

The read is an in-tab fetch of the Series URL, not a DOM render: comix is an
SPA, so rendering costs ~65 requests for the same server-rendered HTML one
fetch returns (24.5 KB, ~480 ms). Parsers and stored Series identity are
untouched.

Verified live against the real browser unit: page 24793 bytes in one fetch,
chapter 53, cover accepted by the pin and 26862 image bytes retrieved by
direct navigation (comix's Series page sets cross-origin-embedder-policy:
require-corp, so an in-page fetch of the cover host cannot work).

REDEPLOY.md

@@ -436,8 +436,8 @@ free -m                     # the Gitea runner should still have its headroom
 
 Nothing here needs doing during an API redeploy. The API stack does not
 `depends_on` the browser, and an unreachable one degrades exactly as an unset
-`BROWSER_WS_URL`: plain-TLS libraries unaffected, kagane and novelfull logged
-and skipped, stored covers still served.
+`BROWSER_WS_URL`: plain-TLS libraries unaffected, kagane and comix logged
+and skipped, novelfull attempted over plain TLS, stored covers still served.
 
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