perf(lyrics): fix CPU spikes during lyric transitions; fix release workflow

CSS: remove `font-weight` from transition list on `.fs-lyric-line` — it
triggers layout reflow on every animation frame when the active line changes.
Replaced with `transform: scaleX(1.015)` on `.fsl-active` (compositor-only).
Added `contain: layout style` to `.fs-lyrics-overlay` to isolate reflows.

Cargo.lock: update for thread-priority crate (added in previous audio commit).

CI: replace delete-asset workaround with `updaterJsonKeepUniversal: false`
to prevent tauri-action from uploading a latest.json with wrong signature.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.github/workflows/release.yml

@@ -124,16 +124,10 @@ jobs:
         with:
           releaseId: ${{ needs.create-release.outputs.release_id }}
           args: ${{ matrix.settings.args }}
-
-      # tauri-action auto-generates a latest.json using the pubkey from tauri.conf.json
-      # as the signature value (wrong). Delete it so only our generate-update-manifest.js
-      # output is ever used as the canonical update manifest.
-      - name: remove tauri-action generated update manifest
-        shell: bash
-        run: |
-          gh release delete-asset ${{ github.ref_name }} latest.json --yes || true
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          # Prevent tauri-action from auto-uploading a latest.json that uses
+          # the PUBLIC KEY as the signature value. Our generate-update-manifest.js
+          # builds the correct manifest with real .sig file contents.
+          updaterJsonKeepUniversal: false
 
       - name: sign and upload Windows NSIS updater bundle
         if: matrix.settings.platform == 'windows-latest'

src-tauri/Cargo.lock

@@ -3442,6 +3442,7 @@ dependencies = [
  "tauri-plugin-store",
  "tauri-plugin-updater",
  "tauri-plugin-window-state",
+ "thread-priority",
  "tokio",
  "url",
 ]
@@ -3513,7 +3514,7 @@ dependencies = [
  "once_cell",
  "socket2 0.6.3",
  "tracing",
- "windows-sys 0.52.0",
+ "windows-sys 0.60.2",
 ]
 
 [[package]]
@@ -5295,6 +5296,20 @@ dependencies = [
  "syn 2.0.117",
 ]
 
+[[package]]
+name = "thread-priority"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cfe075d7053dae61ac5413a34ea7d4913b6e6207844fd726bdd858b37ff72bf5"
+dependencies = [
+ "bitflags 2.11.0",
+ "cfg-if",
+ "libc",
+ "log",
+ "rustversion",
+ "winapi",
+]
+
 [[package]]
 name = "time"
 version = "0.3.45"

src/styles/components.css

@@ -3260,6 +3260,7 @@
   z-index: 3;
   overflow: hidden;
   pointer-events: none;
+  contain: layout style;   /* isolate reflows from rest of page */
 
   /* Fade first and last slot (each 3.6/18 = 20% of container) */
   -webkit-mask-image: linear-gradient(
@@ -3300,7 +3301,9 @@
   font-weight: 400;
   cursor: pointer;
   pointer-events: auto;
-  transition: color 280ms ease, font-weight 280ms ease, text-shadow 280ms ease;
+  /* font-weight intentionally NOT transitioned — triggers layout reflow on every frame */
+  transition: color 280ms ease, text-shadow 280ms ease, transform 280ms ease;
+  transform-origin: left center;
   user-select: none;
 }
 
@@ -3312,11 +3315,12 @@
   color: rgba(255, 255, 255, 0.1);
 }
 
-/* Active: emphasis via weight + glow only, height stays 44px */
+/* Active: emphasis via scale + glow; font-weight snaps instantly (no layout-reflow transition) */
 .fs-lyric-line.fsl-active {
   font-weight: 600;
   color: rgba(255, 255, 255, 0.95);
   text-shadow: 0 0 28px var(--accent-glow, var(--accent)), 0 1px 8px rgba(0, 0, 0, 0.6);
+  transform: scaleX(1.015);   /* subtle compositor-only emphasis, no layout cost */
 }