Replace setTimeout(0) with Svelte's tick() for batching store updates

[Copilot]

setTimeout(0) was used to batch rapid store updates, which is code smell in Svelte apps. Replaced with Svelte's idiomatic tick() function.

Changes

• src/store/layers.ts: Timer-based batching → tick()-based async batching. All synchronous store subscriptions queue mutators before tick() resolves, then flush applies them in one batch.
• src/components/GradientStops.svelte: setTimeout(0) → await tick(). Removed timer cleanup code (unnecessary with promises).

Why tick()

• Microtask queue (faster than macrotask)
• No manual cleanup on unmount
• Already used in LayersPanel.svelte for similar deferred work

Example

// Before
batchUpdateTimer = setTimeout(() => {
  // flush updates
}, 0)

// After  
async function flushPendingUpdates() {
  await tick()
  // All synchronous mutations collected, now flush
}

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.

[netlify]

✅ Deploy Preview for hd-gradients ready!

Name	Link
🔨 Latest commit	2d28c85
🔍 Latest deploy log	https://app.netlify.com/projects/hd-gradients/deploys/697b01e236b71f000826e165
😎 Deploy Preview	https://deploy-preview-122--hd-gradients.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify project configuration.