fix(lint): isolate IIFE timing constants

[miguel-heygen]

Summary

• stop leaking same-named constant values across separate IIFE scopes
• preserve ambiguous position expressions as raw values instead of collapsing them to zero
• prevent phantom overlapping_gsap_tweens findings for those expressions

Test plan

• bun test packages/parsers/src/gsapParserAcorn.full.test.ts (67 pass, 4 skip)
• bun test packages/lint/src/rules/gsap.test.ts (86/86)
• changed-file oxfmt and oxlint checks pass