feat(seo): make paca.chanpaca.net the canonical domain for the whole site

Both hostnames served the same sitemap and feed, so the sitemap submitted for
paca.chanpaca.net listed only mediabrowser.chanpaca.net URLs and Naver rejected
it as not matching the verified domain. Switch every canonical URL, Open Graph
tag, hreflang, JSON-LD, sitemap, RSS feed, llms files, app share link, package
manifest and promo UTM to paca.chanpaca.net, then resubmit the corrected Naver
and Search Console sitemaps. All 2,757 tests pass.

💘 Generated with Crush

Assisted-by: Crush:deepseek-v4.1-flash

docs/promo/global.md

@@ -1,6 +1,6 @@
 # 글로벌 채널 홍보 게시문 (copy-paste)
 
-> 영문 페이지 사용: https://mediabrowser.chanpaca.net/en/
+> 영문 페이지 사용: https://paca.chanpaca.net/en/
 > 모든 런치를 **같은 24~48시간**에 집중해야 GitHub Trending·알고리즘이 반응한다.
 
 ---
@@ -40,7 +40,7 @@ What was hard:
 - Avoiding re-encode: Direct Stream Copy, but only when the segment timeline is clean.
 
 It's a Windows desktop app (WPF + WebView2). Free, no telemetry.
-Docs/spec: https://mediabrowser.chanpaca.net/en/
+Docs/spec: https://paca.chanpaca.net/en/
 Happy to answer anything about the parser or the remux step.
 ```
 > 사전 투표 요청·재게시 금지(ring voting 탐지). 종일 댓글 응대.
@@ -60,8 +60,8 @@ I made Paca: it has a Chromium (WebView2) browser built in, sniffs HLS/DASH/MP4
 
 It's free with no caps. Windows 10/11. Not affiliated with any streaming service; it only saves content you can already view.
 
-Site: https://mediabrowser.chanpaca.net/en/?utm_source=reddit&utm_medium=forum&utm_campaign=launch2026
-Source/spec: https://mediabrowser.chanpaca.net/llms-full.txt
+Site: https://paca.chanpaca.net/en/?utm_source=reddit&utm_medium=forum&utm_campaign=launch2026
+Source/spec: https://paca.chanpaca.net/llms-full.txt
 
 Feedback very welcome, especially edge cases in the HLS parser.
 ```
@@ -90,7 +90,7 @@ page plays and saves lossless MP4 with the session's cookies intact (plus a
 QR-paired Android app for local Wi-Fi streaming). No signup, no caps.
 
 Would love to have it considered for your newsletter/directory.
-https://mediabrowser.chanpaca.net/en/
+https://paca.chanpaca.net/en/
 ```
 
 ---