Move the mouse out of pardes.zig into mouse.zig

Pure move, no behaviour change: handleMouse with dragUpdate, dragRelease,
seamIdxAt, reportGesture, gestureRange, dispatchPointerBuiltin,
mirrorTtySelection and chordCutPaste, the pointer hit helpers
(bodyHitForPane, sameTagCell, tagColumn, sameBodyCell), chromeTarget with
ChromeTarget, paneAt, the Drag state type with clampBorderCol/Row, the seam
test fixtures and thirteen pointer and drag tests go verbatim to mouse.zig.

The methods become free functions taking `p: *Pardes`; their 36 call sites
change from `p.handleMouse(..)` to `mouse.handleMouse(p, ..)`, including
web.zig's chromeTarget and macos.zig's paneAt. The Mouse event type stays
in pardes.zig with the rest of the event vocabulary.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 2 insertions, 1 deletions

diff --git a/src/web.zig b/src/web.zig
index b5a992ae..4c2a9db8 100644
--- a/src/web.zig
+++ b/src/web.zig
@@ -10,6 +10,7 @@
 
 const std = @import("std");
 const pardes = @import("pardes.zig");
+const mouse = @import("mouse.zig");
 
 const gpa = std.heap.wasm_allocator;
 const embedded_dump = @embedFile("embedded.dump.zon");
@@ -441,7 +442,7 @@ export fn pardes_chrome_target(col_arg: u32, row_arg: u32) u32 {
     const s = &(state orelse return std.math.maxInt(u32));
     const col: u16 = @intCast(@min(col_arg, std.math.maxInt(u16)));
     const row: u16 = @intCast(@min(row_arg, std.math.maxInt(u16)));
-    const target = s.core.chromeTarget(col, row) orelse return std.math.maxInt(u32);
+    const target = mouse.chromeTarget(s.core, col, row) orelse return std.math.maxInt(u32);
     return (@as(u32, target.row) << 16) | target.col;
 }