feat(setup): add code signing configuration and status display

- Add SigningDefaults to GlobalDefaults for macOS/Windows/Linux signing config
- Add signing status section to doctor command with platform detection
- Add --json flag to doctor command for machine-readable output
- Add /api/signing and /api/signing/status endpoints to setup wizard
- Add SigningStep component with platform tabs and status indicators
- Wire signing step into wizard flow after projects step

The signing step shows detected signing identities from:
- macOS: keychain codesigning identities, notarization config
- Windows: certificate file/store/cloud, SignTool availability
- Linux: GPG keys from keyring or config

Author: leaanthony

v3/UNRELEASED_CHANGELOG.md

@@ -21,6 +21,10 @@ After processing, the content will be moved to the main changelog and this file
 - Add universal link support for macOS by @APshenkin in [PR](https://github.com/wailsapp/wails/pull/4712)
 - Refactor binding transport layer by @APshenkin in [PR](https://github.com/wailsapp/wails/pull/4702)
 - Add aria-label identifiers to the helloworld templates so that the example app can be easily tested by Appium test clients by @chinenual in [PR](https://github.com/wailsapp/wails/pull/4760)
+- Add code signing configuration to GlobalDefaults for all platforms (macOS, Windows, Linux)
+- Add signing status section to `wails3 doctor` command showing configured signing identities
+- Add `--json` flag to `wails3 doctor` for machine-readable output
+- Add signing step to setup wizard with platform-specific status display
 
 ## Changed
 <!-- Changes in existing functionality -->

v3/cmd/wails3/main.go

@@ -49,7 +49,12 @@ func main() {
 	pkg.Action(func() error {
 		return commands.Package(&pkgFlags, pkg.OtherArgs())
 	})
-	app.NewSubCommandFunction("doctor", "System status report", commands.Doctor)
+	doctorCmd := app.NewSubCommand("doctor", "System status report")
+	var doctorFlags flags.Doctor
+	doctorCmd.AddFlags(&doctorFlags)
+	doctorCmd.Action(func() error {
+		return commands.Doctor(&doctorFlags)
+	})
 	app.NewSubCommandFunction("releasenotes", "Show release notes", commands.ReleaseNotes)
 
 	task := app.NewSubCommand("task", "Run and list tasks")

v3/internal/commands/doctor.go

@@ -2,10 +2,9 @@ package commands
 
 import (
 	"github.com/wailsapp/wails/v3/internal/doctor"
+	"github.com/wailsapp/wails/v3/internal/flags"
 )
 
-type DoctorOptions struct{}
-
-func Doctor(_ *DoctorOptions) error {
-	return doctor.Run()
+func Doctor(options *flags.Doctor) error {
+	return doctor.Run(options.JSON)
 }

v3/internal/defaults/defaults.go

@@ -18,6 +18,9 @@ type GlobalDefaults struct {
 
 	// Default project settings
 	Project ProjectDefaults `json:"project" yaml:"project"`
+
+	// Code signing configuration (optional)
+	Signing SigningDefaults `json:"signing,omitempty" yaml:"signing,omitempty"`
 }
 
 // AuthorDefaults contains the author's information
@@ -38,6 +41,41 @@ type ProjectDefaults struct {
 	UseInterfaces           bool   `json:"useInterfaces" yaml:"useInterfaces"`
 }
 
+// SigningDefaults contains code signing configuration for all platforms
+type SigningDefaults struct {
+	Darwin  DarwinSigningDefaults  `json:"darwin,omitempty" yaml:"darwin,omitempty"`
+	Windows WindowsSigningDefaults `json:"windows,omitempty" yaml:"windows,omitempty"`
+	Linux   LinuxSigningDefaults   `json:"linux,omitempty" yaml:"linux,omitempty"`
+}
+
+// DarwinSigningDefaults contains macOS code signing configuration
+type DarwinSigningDefaults struct {
+	Identity        string `json:"identity,omitempty" yaml:"identity,omitempty"`
+	TeamID          string `json:"teamID,omitempty" yaml:"teamID,omitempty"`
+	KeychainProfile string `json:"keychainProfile,omitempty" yaml:"keychainProfile,omitempty"`
+	Entitlements    string `json:"entitlements,omitempty" yaml:"entitlements,omitempty"`
+	P12Path         string `json:"p12Path,omitempty" yaml:"p12Path,omitempty"`
+	APIKeyPath      string `json:"apiKeyPath,omitempty" yaml:"apiKeyPath,omitempty"`
+	APIKeyID        string `json:"apiKeyID,omitempty" yaml:"apiKeyID,omitempty"`
+	APIIssuerID     string `json:"apiIssuerID,omitempty" yaml:"apiIssuerID,omitempty"`
+}
+
+// WindowsSigningDefaults contains Windows code signing configuration
+type WindowsSigningDefaults struct {
+	CertificatePath string `json:"certificatePath,omitempty" yaml:"certificatePath,omitempty"`
+	Thumbprint      string `json:"thumbprint,omitempty" yaml:"thumbprint,omitempty"`
+	TimestampServer string `json:"timestampServer,omitempty" yaml:"timestampServer,omitempty"`
+	CloudProvider   string `json:"cloudProvider,omitempty" yaml:"cloudProvider,omitempty"`
+	CloudKeyID      string `json:"cloudKeyID,omitempty" yaml:"cloudKeyID,omitempty"`
+}
+
+// LinuxSigningDefaults contains Linux package signing configuration
+type LinuxSigningDefaults struct {
+	GPGKeyPath string `json:"gpgKeyPath,omitempty" yaml:"gpgKeyPath,omitempty"`
+	GPGKeyID   string `json:"gpgKeyID,omitempty" yaml:"gpgKeyID,omitempty"`
+	SignRole   string `json:"signRole,omitempty" yaml:"signRole,omitempty"`
+}
+
 // Default returns sensible defaults for first-time users
 func Default() GlobalDefaults {
 	return GlobalDefaults{