[collapsible] Fix trigger and panel state bugs

[atomiks]

Fix a few Collapsible edge cases and intentionally add the missing regression coverage alongside the fixes.

Root cause

A few paths missed small state checks: the trigger destructured id before forwarding props, initially open panels only cleared mount-animation suppression on one close path, and beforematch opened before honoring canceled change details.

Changes

• Forward id from Collapsible.Trigger.
• Clear open-animation suppression whenever a panel starts closing so later reopens can animate even without close keyframes.
• Honor eventDetails.cancel() for hiddenUntilFound beforematch opens before setting skip/open state.
• Add focused coverage for disabled interactions, controlled and canceled trigger presses, state callbacks, opening starting style, public type exports, and the repaired animation and beforematch cases.

[pkg-pr-new]

• base-ui-tanstack-start

• vite-css-base-ui-example

  pnpm add https://pkg.pr.new/mui/base-ui/@base-ui/react@4848
  

  pnpm add https://pkg.pr.new/mui/base-ui/@base-ui/utils@4848
  

commit: 75a47d7

[code-infra-dashboard]

Bundle size

Bundle	Parsed size	Gzip size
@base-ui/react	▼-3B(0.00%)	▼-4B(0.00%)

Details of bundle changes

Performance

Total duration: 1,064.21 ms -224.60 ms^(-17.4%) | Renders: 50 ⁽⁺⁰⁾ | Paint: 1,617.88 ms -358.07 ms^(-18.1%)

Test	Duration	Renders
Slider mount (300 instances)	146.88 ms ▼-58.07 ms(-28.3%)	3 (+0)
Checkbox mount (500 instances)	60.40 ms ▼-39.27 ms(-39.4%)	1 (+0)
Scroll Area mount (300 instances)	76.10 ms ▼-21.03 ms(-21.7%)	3 (+0)

9 tests within noise — details

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