Replace auto-start with startup automation, add card colors to dashboard

- Add `startup` automation condition type that activates on server boot,
  replacing the per-target `auto_start` flag
- Remove `auto_start` field from targets, scene snapshots, and all API layers
- Remove auto-start UI section and star buttons from dashboard and target cards
- Remove `color` field from scene presets (backend, API, modal, frontend)
- Add card color support to scene preset cards (color picker + border style)
- Show localStorage-backed card colors on all dashboard cards (targets,
  automations, sync clocks, scene presets)
- Fix card color picker updating wrong card when duplicate data attributes
  exist by using closest() from picker wrapper instead of global querySelector
- Add sync clocks step to Sources tab tutorial
- Bump SW cache v9 → v10

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

server/src/wled_controller/static/js/app.js

@@ -36,7 +36,7 @@ import {
 } from './features/devices.js';
 import {
     loadDashboard, stopUptimeTimer,
-    dashboardToggleAutomation, dashboardStartTarget, dashboardStopTarget, dashboardToggleAutoStart, dashboardStopAll,
+    dashboardToggleAutomation, dashboardStartTarget, dashboardStopTarget, dashboardStopAll,
     dashboardPauseClock, dashboardResumeClock, dashboardResetClock,
     toggleDashboardSection, changeDashboardPollInterval,
 } from './features/dashboard.js';
@@ -100,7 +100,7 @@ import {
     startTargetProcessing, stopTargetProcessing,
     stopAllLedTargets, stopAllKCTargets,
     startTargetOverlay, stopTargetOverlay, deleteTarget,
-    cloneTarget, toggleLedPreview, toggleTargetAutoStart,
+    cloneTarget, toggleLedPreview,
     expandAllTargetSections, collapseAllTargetSections,
     disconnectAllLedPreviewWS,
 } from './features/targets.js';
@@ -211,7 +211,6 @@ Object.assign(window, {
     dashboardToggleAutomation,
     dashboardStartTarget,
     dashboardStopTarget,
-    dashboardToggleAutoStart,
     dashboardStopAll,
     dashboardPauseClock,
     dashboardResumeClock,
@@ -356,7 +355,6 @@ Object.assign(window, {
     deleteTarget,
     cloneTarget,
     toggleLedPreview,
-    toggleTargetAutoStart,
     disconnectAllLedPreviewWS,
 
     // color-strip sources