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/directories.md

@@ -2,7 +2,7 @@
 
 > 만성적 검색 유입을 만드는 계층. 모더레이션에 2~3주 걸리므로 런치 3~4주 전 제출.
 > 전제: 설치자 **VirusTotal 청정**, 가능하면 **코드 서명**, 무인 설치 가능.
-> 확정 자산(v1.2.0): 설치자 `https://git.chanpaca.net/Video-Downloader/releases/releases/download/v1.2.0/Paca-Setup-x64.exe` · 아이콘 `https://mediabrowser.chanpaca.net/assets/paca-logo-512.png` · 해시·패키지 매니저 값은 `build/distribution/README.md §7`.
+> 확정 자산(v1.2.0): 설치자 `https://git.chanpaca.net/Video-Downloader/releases/releases/download/v1.2.0/Paca-Setup-x64.exe` · 아이콘 `https://paca.chanpaca.net/assets/paca-logo-512.png` · 해시·패키지 매니저 값은 `build/distribution/README.md §7`.
 
 ---
 
@@ -13,7 +13,7 @@
 
 - **Name**: `Paca`
 - **Short description**: `Free media browser that auto-detects and downloads HLS/DASH/MP4 streams.`
-- **Website**: `https://mediabrowser.chanpaca.net/?utm_source=alternativeto&utm_medium=directory&utm_campaign=evergreen`
+- **Website**: `https://paca.chanpaca.net/?utm_source=alternativeto&utm_medium=directory&utm_campaign=evergreen`
 - **Pricing**: `Free`
 - **Platforms**: `Windows`
 - **Tags**: `Download Manager`, `Video Downloader`, `Streaming`, `Media Player`, `Open Source Alternative`
@@ -47,7 +47,7 @@ subscription.
 ## 3. FileHorse
 - 제출: `https://www.filehorse.com/contact/` 로 아래 10개 항목 전달.
 1. Program name & version (`Paca 1.2.0`)
-2. Website (`https://mediabrowser.chanpaca.net/`)
+2. Website (`https://paca.chanpaca.net/`)
 3. 설치 파일 다운로드 링크 (`.../releases/download/v1.2.0/Paca-Setup-x64.exe`)
 4. License (`Freeware`)
 5. Icon 256×256 (`paca-logo-512.png` 리사이즈)