Windows: resize border from the first frame, DPI-correct window moves (#1396)

* Windows: resize border from the first frame, DPI-correct window moves (#1381)

- The egui resize zones were laid out after the start page's early return, so a launch without
  a design had no resize edges at all. They now run on every page.
- Windows: the main window's procedure answers WM_NCHITTEST with the resize edges and corners,
  Windows' own border width at the window's DPI (8 px at 100 %), so the OS shows its resize
  cursors and runs its own resize (snap included) from the first message; no egui zones there.
- Windows: WM_GETDPISCALEDSIZE returns the size winit then applies (same logical size), so the
  rect the OS suggests while the title bar is dragged onto a monitor with another scale is the
  rect the window gets.
- Zone sizes and hit test shared in titlebar.rs and unit-tested; Windows CI checks the hit test
  right after launch and a real edge drag.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Windows resize smoke: find the main window by its title

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Windows resize smoke: probe the maximized window at the screen's edge

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

apps/solidcraft/Cargo.toml

@@ -8,8 +8,8 @@ publish = false
 default-run = "solidcraft"
 
 # The workspace lints, except unsafe_code: denied, not forbidden, so that src/open_documents.rs
-# (macOS file-open events) and src/native_crash.rs (Windows exception filter) can allow it: neither
-# has a safe API. Keep the rest in sync with [workspace.lints].
+# (macOS file-open events), src/native_crash.rs (Windows exception filter) and src/native_frame.rs
+# (Windows resize border) can allow it: none has a safe API. Keep the rest in sync with [workspace.lints].
 [lints.rust]
 unsafe_code = "deny"
 
@@ -42,7 +42,10 @@ quick-xml = { workspace = true }
 
 [target.'cfg(target_os = "windows")'.dependencies]
 hidapi = { version = "2.6.7", default-features = false, features = ["windows-native"] }
+# The main window's handle for src/native_frame.rs (already in the tree through eframe and winit).
+raw-window-handle = "0.6"
 # Native crash capture (src/native_crash.rs): the exception filter, the faulting module, a minidump.
+# The window's resize border and DPI size (src/native_frame.rs): the window procedure, hit test, DPI.
 windows-sys = { version = "0.61", features = [
     "Win32_Foundation",
     "Win32_Security",
@@ -53,6 +56,8 @@ windows-sys = { version = "0.61", features = [
     "Win32_System_LibraryLoader",
     "Win32_System_Memory",
     "Win32_System_Threading",
+    "Win32_UI_HiDpi",
+    "Win32_UI_WindowsAndMessaging",
 ] }
 
 [target.'cfg(target_os = "macos")'.dependencies]