feat(pet): add click-to-pet interaction with bounce, hearts & reactions

[aiexkwan]

Summary

• Click the pet to trigger a playful squash-and-stretch bounce animation, floating heart particles, a reaction speech bubble, and a "Pop" sound effect
• Three escalating reaction tiers based on consecutive clicks within 3 seconds:
  • 1-2 taps: casual ("Hehe~", "That tickles!", "purrs")
  • 3-5 taps: happy ("I love you! 💕", "More pets please!")
  • 6+ taps: excited ("MAXIMUM LOVE! 💖", "I'm gonna melt~")
• Fully independent of the existing mood/agent session system — tapping never changes the pet's mood, clears agent bubbles, or interferes with working/waiting state display

Design details

Component	Implementation
Bounce	Squash-stretch via scaleEffect with interpolatingSpring (stiffness 300, damping 8)
Hearts	5 pink hearts float upward and fade out over 0.8s, recreated each tap via .id()
Reaction bubble	Frosted glass capsule (.regularMaterial) overlaid at pet's top, auto-dismisses after 2s
Sound	macOS system "Pop" sound
Cooldown	0.4s between taps to prevent animation/sound stacking
Consecutive tracking	3s window, resets on pause

Test plan

• swift build — compiles cleanly
• swift test — 194 tests, 0 failures, no regressions
• Manual: click pet while idle → bounce + hearts + reaction bubble + sound
• Manual: rapid-click 6+ times → reaction escalates through all 3 tiers
• Manual: click pet while agents are working → agent status bubble stays intact
• Manual: drag pet after adding tap gesture → window drag still works

🤖 Generated with Claude Code

[ntd4996]

Merged and shipped in v1.5.0 🎉 Love this one, the squash-and-stretch bounce with the floating hearts feels great, and keeping it fully separate from the agent/mood state was exactly the right call. Tested locally: drag, agent bubbles and the tap reactions all play nicely together. Thanks!