macos: pixel attachments, live theming, and a signed app

The AppKit shell now draws what the core renders, follows the theme without a
relaunch, and builds into something you can hand to someone.

- Pixel attachments. Surface.images was dropped on the floor here, so a PDF
  pane showed nothing at all: native_images is now set, pardes_image_s carries
  the geometry the core already clipped, and PardesView keeps one CGImage per
  (serial, page, revision) so scrolling costs a draw and not a decode. Image
  panes get real pixels instead of the petscii fallback.

- Themes take hold live. pardes_tick never advanced the chrome animation, so
  every tagline kept the previous theme's colours until the next launch and
  the 16 ms re-pump spun for the rest of the session. pardes_theme_bg retires
  the hand-agreed #121212 and drives the window background and the titlebar
  appearance; a theme with no background of its own now gets a transparent
  window over an NSVisualEffectView.

- The cell snaps to whole DEVICE pixels rather than whole points. Monaco
  advances 8.4014pt at 14, so ceiling to 9 spaced every column 7.1% wider than
  the face was drawn for.

- The dial is one notch per 10 degrees instead of 20, and a release keeps
  turning in proportion to how hard it was thrown -- ramping up from zero at
  the floor, so a slow twist coasts not a little but not at all.

- A file dropped on the grid is a click plus Look, so it opens beside the pane
  it was dropped on. No drop concept was added to the core.

- The titlebar follows the focused pane: proxy icon, filename, and the dirty
  dot. File.saved_revision is the watermark that last one needed.

- Config (SPC f c) prints the resolved startup config path.

- build.zig assembles, signs and packages the bundle itself; build-app.sh is
  gone. -Dmacos-identity= takes a Developer ID, macos-dmg makes the image, and
  the icon is Glenda.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/nested.zig b/src/nested.zig
index a8fd021d..0db38ad9 100644
--- a/src/nested.zig
+++ b/src/nested.zig
@@ -552,8 +552,8 @@ test "the app bundle is the same build as the binary installed beside it" {
         "/work/zig-out/bin/pardes-gui",
     ));
     // The case this machine actually produces: `zig build` installs the tty
-    // binary under its os-arch tail, and build-app.sh copies the same build
-    // into a bundle where it can only be called `pardes`.
+    // binary under its os-arch tail, and the bundle carries the same build
+    // under the one name CFBundleExecutable can spell.
     try std.testing.expect(samePardesExecutable(
         "/work/zig-out/pardes.app/Contents/MacOS/pardes",
         "/work/zig-out/bin/pardes-macos-aarch64",