fix(oaktimeline): placement sets the block's in point (drop-at-cursor fix)

TrackPlaceBlockCommand::redo now homes the block's in point to the
placement target (capturing the original for undo): the Rust block
stores its position on the block, so a fresh clip that never had its
in point set always rendered at the timeline zero — the 'drops always
land at zero' bug. The original in point is captured on the first redo
and restored on undo, keeping the sync re-place round-trip exact. The
A/V drop test now asserts the clip lands at the drop frame.

crates/oaktimeline/src/undopointer.rs

@@ -556,6 +556,9 @@ pub struct TrackPlaceBlockCommand {
 	add_track_commands_: Vec<TimelineAddTrackCommand>,
 	/// Ripple-removal of the area the block occupies (`ripple_remove_command_`).
 	ripple_remove_command_: Option<TrackRippleRemoveAreaCommand>,
+	/// The block's in point captured on the first redo (restored on undo
+	/// so a sync re-place / move round-trips the original position).
+	old_in_: Option<Rational>,
 }
 
 impl TrackPlaceBlockCommand {
@@ -572,11 +575,22 @@ impl TrackPlaceBlockCommand {
 			block,
 			add_track_commands_: Vec::new(),
 			ripple_remove_command_: None,
+			old_in_: None,
 		}
 	}
 
 	/// `redo`: place the block destructively.
 	pub fn redo(&mut self) {
+		// The module stores the position on the block (no track-order
+		// derivation like C++), so the placement contract is that the
+		// block's in point becomes `in_` — fresh clips otherwise keep
+		// their birth in=0 and every drop lands at the timeline zero. The
+		// original position is captured once so undo restores it (the
+		// sync re-place path round-trips the block's position).
+		if self.old_in_.is_none() {
+			self.old_in_ = Some(block_in(&self.block));
+		}
+		block_set_in(&self.block, self.in_);
 		// Determine if we need to add tracks
 		let track_count = tracklist_track_count(&self.timeline) as i32;
 
@@ -655,6 +669,10 @@ impl TrackPlaceBlockCommand {
 
 		// Firstly, remove our insert
 		track_ripple_remove_block(&t, &self.block);
+		// Restore the position the block had before the placement.
+		if let Some(old_in) = self.old_in_ {
+			block_set_in(&self.block, old_in);
+		}
 
 		if self.ripple_remove_command_.is_some() {
 			// If we ripple-removed, just undo that

src/oakui/real.rs

@@ -6225,9 +6225,21 @@ mod tests {
 		.expect("imported footage is listed");
 		cx.update(|app| {
 			engine.update(app, |engine, cx| {
-				engine.drop_footage(entry.id, TrackKind::Video, 0, Frame(0), cx)
+				// Drop at a non-zero frame: the placement must land where
+				// the cursor was (the "always lands at zero" regression).
+				engine.drop_footage(entry.id, TrackKind::Video, 0, Frame(40), cx)
 			})
 		});
+		// The clip landed at the drop frame (not the timeline zero).
+		let video_in = cx.read(|app| {
+			let engine = engine.read(app);
+			engine
+				.tracks
+				.iter()
+				.find(|t| t.kind == TrackKind::Video && !t.clips.is_empty())
+				.map(|t| t.clips[0].range.start.0)
+		});
+		assert_eq!(video_in, Some(40), "the clip lands at the drop frame");
 
 		let clip_count = |engine: &RealEngine, kind: TrackKind| -> usize {
 			engine