Fix event listener accumulation on repeated init() calls

[Sanchit2662]

🛠 Fix: Prevent Event Listener Accumulation on Section Navigation

Impact

Phoenix uses a root-level EventDisplayService that stays alive while navigating between sections (ATLAS, CMS, LHCb, TrackML, etc.).
Each section calls eventDisplay.init() on navigation, which caused global event listeners to be re-registered every time without removing the old ones.

Over multiple navigations, this led to:

• Growing numbers of resize, keydown, and OrbitControls listeners
• Noticeable performance degradation
• Window resize becoming sluggish
• Keyboard shortcuts triggering multiple times
• Old Three.js objects being retained in memory

This issue directly affects normal Phoenix usage, especially when users compare multiple detectors in a single session.

---

Steps to Reproduce

1. Open Phoenix in Chrome and open DevTools → Console

2. Navigate through several sections:

   Home → ATLAS → CMS → LHCb → TrackML → Playground
   

3. After each navigation, run:

   getEventListeners(window).resize.length

Before the fix:
The listener count increases on every navigation.

Expected behavior:
Listener count should remain constant.

---

Root Cause

• EventDisplayService is a singleton (providedIn: 'root')
• init() is called on every section navigation
• init() assumes a fresh instance and registers global listeners
• Listeners were added using anonymous callbacks, so they could not be removed
• No cleanup occurred before re-initialization

This resulted in unbounded listener accumulation over time.

---

Fix

The fix introduces explicit lifecycle cleanup and makes re-initialization safe:

• EventDisplay now cleans up before re-initializing
• Global event listeners are stored as class-level references
• Existing listeners are removed before adding new ones
• Cleanup methods ensure no stale listeners remain

Minimal example:

if (this.isInitialized) {
  this.cleanup();
}

window.removeEventListener('resize', this.resizeHandler);

This pattern is applied consistently across renderer, controls, and keyboard handlers.

---

Result

• Event listener counts stay constant regardless of navigation
• Window resize remains responsive
• Keyboard shortcuts execute once per key press
• Memory remains stable during long sessions
• No functional regressions observed

---

Notes

• Section components were left unchanged
• No public APIs were modified
• Changes are limited strictly to listener lifecycle management
• Verified using DevTools listener inspection and performance monitoring

[Sanchit2662]

Hi, @EdwardMoyse
This PR fixes an issue where global event listeners were accumulating on each section navigation due to repeated EventDisplay.init() calls on a singleton service.

Thanks for maintaining Phoenix and for taking the time to review this! 🙏