fix(selection): drop stale selection indices after undo, redo and clear (0.3.5)

[markm39]

Problem

OpenNotes 1.3.2 App Store reviews report crashes "during work" while drawing. This PR reproduces a deterministic crash in the shipped 0.3.4 engine and fixes it.

Selection (selectedIndices_), the object eraser (pendingDeleteIndices_) and selection transforms store positions into strokes_. Undo, redo, clear, load and object erase rebuild or compact strokes_ without invalidating those positions.

• Crash: lasso two strokes, tap Undo, then tap Delete on the selection toolbar (it stays visible). remainingStrokes.reserve(strokes.size() - selectedIndices.size()) underflows size_t, reserve throws std::length_error, and the exception reaches the Swift boundary. The result is std::terminate / SIGABRT.
• Silent data loss: draw A, B, C. Delete A, select C, then Undo. Delete now removes B, which the user never selected. Move and transform can also hit the wrong strokes, and undo during an in-flight transform corrupted geometry.

Fix

• SkiaDrawingEngine::resetIndexedSelectionState() drops index-based selection, object-eraser and drag state. It runs wherever strokes_ is rebuilt or compacted: undo, redo, clear, deserialize and object erase.
• An in-flight selection transform is cancelled before history is reverted or snapshotted.
• reserve() is bounded by the strokes actually removed, so it cannot underflow.
• deleteSelection no longer commits an empty undo entry.
• iOS: after undo, redo or clear, the view ends any move or transform gesture and refreshes the selection toolbar and onInkSelectionChange. Android already re-emitted this, and it shares cpp/.

Evidence

The new scripts/selection_history_smoke.cpp (npm run test:native:selection-smoke, added to CI and validate) has 9 assertions.

• Shipped 0.3.4 engine: 9 assertions fail, including deleteSelection threw after undo: vector (the length_error).
• This branch: all 9 pass, and also pass under AddressSanitizer.
• Other checks: test:native:smoke, test:native:eraser-smoke, jest (82/82), typecheck and test:release all pass.
• Swift: swiftc -typecheck passes for the module against the iOS 26.5 simulator SDK and the React prebuilt framework.

Release

Bumps the version to 0.3.5 with a CHANGELOG entry. Compared with the published 0.3.4, the only shipped-code change is this fix.