feat(lint): warn on repeated tl.fromTo() on one selector without a tl.set baseline [P2]

[miguel-heygen]

Bug

tl.fromTo(SELECTOR, { from }, { to }, laterTime) applies its from values
to the DOM at authoring time (GSAP's immediateRender), regardless of the
tween's timeline position. When the same string-literal selector gets 2+
tl.fromTo() calls with no earlier tl.set() baseline, the last-authored
from becomes the element's resting state for any seek before the first
tween actually runs, e.g. a z-index:999 overlay rendered solid black across
~40% of the timeline. hyperframes lint/validate/inspect all pass clean
today for this pattern.

Fix

New warning-severity rule: gsap_repeated_fromto_without_baseline, extending
the existing GSAP static analysis in packages/lint/src/rules/gsap.ts.

Per script/timeline: groups fromTo GSAP windows by target selector; for any
selector with 2+ fromTo calls, checks for a tl.set/gsap.set baseline on
that exact selector (before or at the first fromTo). If no baseline exists,
fires one finding per offending selector with a fixHint suggesting
tl.set(selector, { ...safe resting values... }, 0).

False-positive guards

This repo has a real history of GSAP false positives, so the rule is
conservative:

• Byte-identical string-literal selector matching only, no normalization or
  token/substring matching.
• Selectors the parser can't statically resolve (dynamic/variable selectors)
  never fire.
• A single fromTo call on a selector never fires.
• Two fromTo calls on different selectors never fire together.
• Any tl.set/gsap.set on the exact same literal selector suppresses the
  finding.

Tests

Added 4 tests to packages/lint/src/rules/gsap.test.ts:

• warns when repeated tl.fromTo calls target one selector without a
  tl.set baseline
• does not warn when repeated tl.fromTo calls have an earlier tl.set
  baseline
• does not warn for a single tl.fromTo call on a selector
• does not warn when tl.fromTo calls target different selectors

bunx vitest run packages/lint/src/rules/gsap.test.ts: 86 passed.
bunx oxlint / bunx oxfmt --check: clean.