Release workflow: publish suffixed tags (alpha/beta) as GitHub prereleases

A tag containing a "-" now stamps its version into the *published*
manifest.json only (master stays at the last stable version) and sets
prerelease: true, so the official updater and community review never see
it while BRAT / manual install can. Process docs: RELEASING.md
"Pre-release (alpha/beta) builds".

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.github/workflows/release.yml

@@ -2,6 +2,10 @@ name: Release
 
 # Build, attest provenance, and publish release assets when a version tag is pushed.
 # Obsidian tags are bare versions with no leading "v" (e.g. 1.0.0).
+# A tag carrying a pre-release suffix (a "-", e.g. 1.3.0-alpha / 1.3.0-beta.1) is
+# published as a GitHub *prerelease*: GitHub's "latest release" (what Obsidian's
+# updater reads) excludes prereleases, so the official channel never sees it, while
+# BRAT / manual install still can. See docs/RELEASING.md.
 on:
   push:
     tags:
@@ -28,6 +32,33 @@ jobs:
       - name: Install dependencies
         run: npm ci
 
+      # A tag with a "-" (e.g. 1.3.0-alpha) is a pre-release channel.
+      - name: Determine release channel
+        id: channel
+        shell: bash
+        run: |
+          if [[ "${{ github.ref_name }}" == *-* ]]; then
+            echo "prerelease=true" >> "$GITHUB_OUTPUT"
+          else
+            echo "prerelease=false" >> "$GITHUB_OUTPUT"
+          fi
+
+      # Master's manifest.json stays at the last stable version during alpha/beta
+      # testing, so stamp the tag's version into the *published* manifest only.
+      # (Stable tags publish manifest.json as committed; this step is skipped.)
+      - name: Stamp pre-release version into manifest
+        if: steps.channel.outputs.prerelease == 'true'
+        shell: bash
+        env:
+          TAG: ${{ github.ref_name }}
+        run: |
+          node -e '
+            const fs = require("fs");
+            const m = JSON.parse(fs.readFileSync("manifest.json", "utf8"));
+            m.version = process.env.TAG;
+            fs.writeFileSync("manifest.json", JSON.stringify(m, null, "\t"));
+          '
+
       - name: Build
         run: npm run build
 
@@ -44,6 +75,7 @@ jobs:
         with:
           tag_name: ${{ github.ref_name }}
           name: ${{ github.ref_name }}
+          prerelease: ${{ steps.channel.outputs.prerelease }}
           files: |
             main.js
             manifest.json