fix(website): relabel install strip "Published to" → "Available on"

The homepage logos strip is filtered to push-mechanism channels,
which includes Flatpak and Obsidian. Those are not published to a
registry — the `.flatpak` and `.zip` bundles are built in CI and
attached to a GitHub release, then installed from the file. So
"Published to Flatpak/Obsidian" was inaccurate.

"Available on" is correct for every channel in the strip (npm,
PyPI, GitHub Releases, the Visual Studio Marketplace, Open VSX,
Flatpak, Obsidian) regardless of whether mdsmith pushes to a
registry or bundles into a release. Update the website/README.md
reference to the strip to match.

Author: claude

website/README.md

@@ -105,7 +105,7 @@ release-channel docs, gated against drift in CI:
   `hugo.Data.channels` (the generated
   `website/data/channels.yaml`). It renders every channel
   with platform-tag filter chips.
-- **"Published to" strip** — the release-channel docs
+- **"Available on" strip** — the release-channel docs
   `../docs/development/release-channels/*.md`. Each
   carries a canonical `channelurl:` and an ordering
   `weight:`; `logos-strip.html` ranges the synced

website/layouts/partials/logos-strip.html

@@ -1,7 +1,7 @@
 <div class="logos">
   <div class="container">
     <div class="logos-strip">
-      <span class="logos-label">Published to</span>
+      <span class="logos-label">Available on</span>
       {{- /* Sourced from the generated install data
              (website/data/channels.yaml, produced by
              `mdsmith-release sync-channels` from