Add per-tab tutorials, profile expand/collapse, and fix card animation

- Add sub-tutorials for Dashboard, Targets, Sources, and Profiles tabs
  with ? trigger buttons, en/ru/zh translations, and hidden-ancestor
  skip via offsetParent check
- Add expand/collapse all buttons to Profiles tab toolbar
- Move dashboard poll slider from section header to toolbar
- Fix cardEnter animation forcing opacity:1 on disabled profile cards
- Use data-card-section selectors instead of data-cs-toggle to avoid
  z-index misalignment during tutorial spotlight
- Add tutorial sync convention to CLAUDE.md

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

CLAUDE.md

@@ -182,6 +182,15 @@ For range sliders, display the current value **inside the label** (not in a sepa
 
 Do **not** use a `range-with-value` wrapper div.
 
+### Tutorials
+
+The app has an interactive tutorial system (`static/js/features/tutorials.js`) with a generic engine, spotlight overlay, tooltip positioning, and keyboard navigation. Tutorials exist for:
+- **Getting started** (header-level walkthrough of all tabs and controls)
+- **Per-tab tutorials** (Dashboard, Targets, Sources, Profiles) triggered by `?` buttons
+- **Device card tutorial** and **Calibration tutorial** (context-specific)
+
+When adding **new tabs, sections, or major UI elements**, update the corresponding tutorial step array in `tutorials.js` and add `tour.*` i18n keys to all 3 locale files (`en.json`, `ru.json`, `zh.json`).
+
 ## General Guidelines
 
 - Always test changes before marking as complete