chore: bump version to 1.4.7, sync changelog and forge post

- csproj <Version> -> 1.4.7
- repo.json AssemblyVersion + TestingAssemblyVersion -> 1.4.7.0
- repo.json DownloadLink{Install,Update,Testing} URLs -> /v1.4.7/
- repo.json + HellionChat.yaml changelog: prepend v1.4.7 block, retire
  v1.4.3 (slim rule keeps the last 3-4 versions)
- docs/CHANGELOG.md + docs/ROADMAP.md: v1.4.7 section, next-cycle
  pointer flipped to v1.4.8 Hook-Layer-Cycle
- README.md release badge + version stamps + Project Status block
  rewritten for v1.4.7
- .github/forge-posts/v1.4.7.md (new): DE body with subtitle
  "Backlog Cleanup and Mid-Features" / versionsnatur "Mid-Feature-Patch"
- Pin diagnostic logs (RehydratePinnedTabs / TryPin / Unpin /
  PromoteToPermanent) downgraded from Info to Debug so non-debug
  console stays quiet on release builds

HellionChat/HellionChat.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Dalamud.NET.Sdk/15.0.0">
     <PropertyGroup>
         <!-- Independent versioning; see yaml changelog for upstream Chat 2 base -->
-        <Version>1.4.6</Version>
+        <Version>1.4.7</Version>
         <ImplicitUsings>enable</ImplicitUsings>
         <Nullable>enable</Nullable>
         <!-- Use lock file to pin exact versions -->