feat(app): implement basic function

General
- 配置界面支持配置对象存储桶
- 快捷键进入截图
- 一键上传截图 & 复制截图链接

MacOS
- 状态栏指示器和应用图标

internal/infrastructure/display/display.go

@@ -0,0 +1,25 @@
+// Package display exposes platform-specific helpers for reading the
+// geometry of the primary display, in both CSS (logical) and PHYSICAL
+// pixels. The overlay flow needs both: CSS pixels to size the Wails window
+// to "fullscreen" (since Wails uses CSS-px-equivalent units), and the
+// backing scale factor to translate the user's CSS-px selection rectangle
+// into the physical-pixel rectangle of the captured PNG.
+package display
+
+// Info describes the primary display.
+//
+// The struct is deliberately minimal: only the few fields the overlay flow
+// actually needs. We can grow it later without affecting callers because
+// it is returned by value.
+type Info struct {
+	// CSSWidth / CSSHeight are the logical dimensions of the primary
+	// display in points (i.e. what CSS / Wails uses).
+	CSSWidth  int
+	CSSHeight int
+
+	// Scale is backing factor (CSS-px → device-px). 2 on Retina, 1 on
+	// non-Retina. We model it as float64 to leave room for fractional
+	// scales (e.g. Linux 1.25×) even though macOS effectively only ever
+	// reports 1 or 2.
+	Scale float64
+}

internal/infrastructure/display/display_darwin.go

@@ -0,0 +1,41 @@
+//go:build darwin
+
+package display
+
+/*
+#cgo LDFLAGS: -framework CoreGraphics -framework Foundation
+#include <CoreGraphics/CoreGraphics.h>
+
+// readPrimaryDisplay fills the four out-params with:
+//   - cssW / cssH    : logical (point) dimensions of the main display
+//   - pxW  / pxH     : physical (device-pixel) dimensions
+// Using CGDisplayBounds for points and CGDisplayPixelsWide/High for pixels
+// is the canonical way to derive the backing scale on macOS without
+// bringing AppKit into the build (we do not want to link Cocoa here).
+static void readPrimaryDisplay(int* cssW, int* cssH, int* pxW, int* pxH) {
+    CGDirectDisplayID id = CGMainDisplayID();
+    CGRect bounds = CGDisplayBounds(id);
+    *cssW = (int)bounds.size.width;
+    *cssH = (int)bounds.size.height;
+    *pxW  = (int)CGDisplayPixelsWide(id);
+    *pxH  = (int)CGDisplayPixelsHigh(id);
+}
+*/
+import "C"
+
+// Primary returns the geometry of the main display. The CGo call has no
+// failure path — the OS always reports a main display whenever there is at
+// least one attached, which is implied for any GUI process.
+func Primary() Info {
+	var cssW, cssH, pxW, pxH C.int
+	C.readPrimaryDisplay(&cssW, &cssH, &pxW, &pxH)
+	scale := 1.0
+	if cssW > 0 {
+		scale = float64(pxW) / float64(cssW)
+	}
+	return Info{
+		CSSWidth:  int(cssW),
+		CSSHeight: int(cssH),
+		Scale:     scale,
+	}
+}

internal/infrastructure/display/display_other.go

@@ -0,0 +1,21 @@
+//go:build !darwin
+
+package display
+
+import "github.com/kbinani/screenshot"
+
+// Primary returns the dimensions of display 0. We currently assume a 1× DPR
+// because Wails on Windows / Linux already paints in physical pixels, so
+// CSS coordinates and capture coordinates coincide. If a user ever runs at
+// non-1× we will add a platform-specific scale lookup.
+func Primary() Info {
+	if screenshot.NumActiveDisplays() == 0 {
+		return Info{CSSWidth: 1440, CSSHeight: 900, Scale: 1}
+	}
+	b := screenshot.GetDisplayBounds(0)
+	return Info{
+		CSSWidth:  b.Dx(),
+		CSSHeight: b.Dy(),
+		Scale:     1,
+	}
+}