feat: run preset animations in screenshot mode for OBS recording

[Shivansh1205]

Problem

There was no way to run preset animations while in screenshot mode, making it impossible to cleanly record them with OBS or similar screen capture software.

Solution

UI — "in Screenshot Mode" button

Each preset in the animate-camera menu now has a second option labelled <preset> (screenshot mode). Clicking it:

1. Enters fullscreen/screenshot mode
2. Runs the preset animation
3. Automatically exits screenshot mode when the animation completes

URL trigger — ?ss=preset-name

Append ?ss=Cavern+to+ID to any Phoenix URL to auto-start a preset in screenshot mode once all assets have loaded. Ideal for sharing a recording-ready link.

Example: https://hepsoftwarefoundation.org/phoenix/?ss=Cavern+to+ID

Files changed

• ss-mode.component.ts — refactored into enterSSMode(onReady?) / exitSSMode() with @Output ssModeExited
• animate-camera.component.ts/html — added animatePresetInSSMode() and per-preset screenshot mode buttons
• event-display.ts — added animatePresetInSSMode(presetName, presets) to public API
• url-options-manager.ts — added applySSAnimationOption() for ?ss= URL param