Switch remote deploy to vendored source builds

Move remote deployment to a vendored source bundle built on the target host via Docker so redeploys no longer require local cross-compilation or host Go installation.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

vendor/github.com/wailsapp/wails/v2/pkg/assetserver/mimecache.go

@@ -0,0 +1,67 @@
+package assetserver
+
+import (
+	"net/http"
+	"path/filepath"
+	"sync"
+
+	"github.com/wailsapp/mimetype"
+)
+
+var (
+	mimeCache = map[string]string{}
+	mimeMutex sync.Mutex
+
+	// The list of builtin mime-types by extension as defined by
+	// the golang standard lib package "mime"
+	// The standard lib also takes into account mime type definitions from
+	// etc files like '/etc/apache2/mime.types' but we want to have the
+	// same behavivour on all platforms and not depend on some external file.
+	mimeTypesByExt = map[string]string{
+		".avif": "image/avif",
+		".css":  "text/css; charset=utf-8",
+		".gif":  "image/gif",
+		".htm":  "text/html; charset=utf-8",
+		".html": "text/html; charset=utf-8",
+		".jpeg": "image/jpeg",
+		".jpg":  "image/jpeg",
+		".js":   "text/javascript; charset=utf-8",
+		".json": "application/json",
+		".mjs":  "text/javascript; charset=utf-8",
+		".pdf":  "application/pdf",
+		".png":  "image/png",
+		".svg":  "image/svg+xml",
+		".wasm": "application/wasm",
+		".webp": "image/webp",
+		".xml":  "text/xml; charset=utf-8",
+	}
+)
+
+func GetMimetype(filename string, data []byte) string {
+	mimeMutex.Lock()
+	defer mimeMutex.Unlock()
+
+	result := mimeTypesByExt[filepath.Ext(filename)]
+	if result != "" {
+		return result
+	}
+
+	result = mimeCache[filename]
+	if result != "" {
+		return result
+	}
+
+	detect := mimetype.Detect(data)
+	if detect == nil {
+		result = http.DetectContentType(data)
+	} else {
+		result = detect.String()
+	}
+
+	if result == "" {
+		result = "application/octet-stream"
+	}
+
+	mimeCache[filename] = result
+	return result
+}