Add butterfly/parrot/wiggle-dog companions; scale mascot + tips

- Three new Lottie companions: Wiggle Dog (摇尾狗), Butterfly (蝴蝶),
  Parrot (鹦鹉). Parrot is mirrored via a new `flip` flag on Companion,
  threaded through LottiePlayer (scaleX(-1)) since the asset faces left.
- Mascot size now scales with the viewport: --petal-companion-size
  clamp(10rem, 17vw, 20rem); art, emoji fallback, and the sleep "z" all
  derive from it.
- Larger, more legible tip bubble (1.4rem zh / 1.15rem en, wider bubble).
- Bubbles linger longer for a bilingual ESL read: baseline 9s→14s,
  cheer 6s→9s, per-char 45→55ms, cap 20s→32s.

Claude-Session: https://claude.ai/code/session_016Yr6jELuRc7hyzYLccQKZd

web/src/components/Companion/useCompanion.ts

@@ -47,10 +47,10 @@ const PROACTIVE_GAP = 40_000 // floor between any two unsolicited bubbles
 // How long a bubble lingers. These are *floors* — readBubbleMs extends them by
 // how much there is to read, since she reads both the Mandarin and the English
 // (and tips now quote a slice of her own sentence, so they run longer).
-const BUBBLE_MS = 9_000 // baseline for a tip / break
-const CHEER_MS = 6_000 // a short cheer still needs a beat in two languages
-const READ_MS_PER_CHAR = 45 // ~22 chars/sec, generous for a bilingual read
-const MAX_BUBBLE_MS = 20_000 // cap so a long quote can't pin the bubble forever
+const BUBBLE_MS = 14_000 // baseline for a tip / break
+const CHEER_MS = 9_000 // a short cheer still needs a beat in two languages
+const READ_MS_PER_CHAR = 55 // ~18 chars/sec, generous for a bilingual ESL read
+const MAX_BUBBLE_MS = 32_000 // cap so a long quote can't pin the bubble forever
 const HOVER_GRACE_MS = 3_000 // lingers this long after she stops hovering
 const now = () => Date.now()