fix: extend CORS origins to comix and kagane, preserve progress on unparseable chapters

- .env.example, DEPLOY.md, docker-compose.yml: add comix.to/kagane.to to
  ALLOWED_ORIGINS so the userscript isn't CORS-blocked on either new site
- .env.example: comment out BROWSER_WS_URL's DNS-name default, which
  overrides the working compose default and 500s Chrome's DevTools handler
- userscript: updateToCurrentChapter() now falls back to the stored
  chapter/label when chapterNum is unparseable, instead of wiping progress
  (kagane's og:title lacks a number when a chapter has no episode suffix)
- README.md: document comix/kagane in the config table, adapter reference,
  and key examples

.env.example

@@ -5,8 +5,8 @@
 API_TOKEN=changeme-generate-a-long-random-token
 
 # Comma-separated origins allowed to call the API (CORS). Both Asura domains
-# plus Demonic. Add/remove as the sites' hostnames change.
-ALLOWED_ORIGINS=https://asuracomic.net,https://asurascans.com,https://demonicscans.org
+# plus Demonic, Comix, and Kagane. Add/remove as the sites' hostnames change.
+ALLOWED_ORIGINS=https://asuracomic.net,https://asurascans.com,https://demonicscans.org,https://comix.to,https://kagane.to
 
 # --- Prod override (Traefik) only ---
 # Subdomain Traefik routes to this service (required by the prod override).
@@ -55,4 +55,8 @@ WEB_PASSWORD=
 
 # Headless-shell CDP endpoint for sites behind a JavaScript challenge (kagane).
 # Unset disables browser polling; those sites then rely on the userscript alone.
-BROWSER_WS_URL=ws://headless-shell:9222
+# Leave commented — the compose files' own default (ws://172.28.0.10:9222) is
+# correct. Do NOT set this to the "headless-shell" DNS name: Chrome's DevTools
+# HTTP handler 500s any /json/version request whose Host header isn't an IP or
+# "localhost", which silently breaks every kagane poll.
+# BROWSER_WS_URL=ws://172.28.0.10:9222