[muukii]

Self-sizing sheets can synchronously reenter their host's layout when body bounds change during .autoPointsFromBottom measurement. The reported Duo stack repeats the container notification and host layout until it crashes.

Separate body-bounds observations from explicit sizing requests and guard the whole host layout transaction. Defer reentrant requests until the current UIKit stack returns, preserving the previous vertical geometry so supplied animators can animate the new height. Coalesce mixed requests without dropping animator completions, retain safe-area propagation before fitting, and avoid redundant constraint assignments.

Validation:

• All 19 package tests passed on iPhone 18 Pro / iOS 27.0 and a dedicated iPhone Duo / iOS 27.1, on both patched main and the 2.5.0 backport.
• New regressions fail on 2.5.0 for synchronous parent layout and nested fitting, then pass with the fix. They also check both resizing options, intermediate presentation heights and completions, and hosted SwiftUI reflow with safe-area and size changes.
• In a dedicated Duo lab linked to the 2.5.0 backport, visible-area and fixed-body sizing, Auto/70% snaps, content grow/shrink, Open/Closed folding, and rotation kept the sheet usable. In fixed-body mode, the actual software keyboard appeared, accepted an on-screen key, and dismissed with the sheet restored; input persisted across folding. Captured process logs contain no observation feedback loop, EXC_BAD_ACCESS, or unsatisfiable-constraint messages during this pass.
• Full consuming-app integration remains to be verified; Pairs still pins 2.5.0 and needs a separate dependency update.

The 2.5.0 backport is preserved on muukii/prevent-self-sizing-layout-reentry; this PR retains main's current drag handling and intrinsic-size observation.