feat: bootstrap temporserv project scaffold

Add the initial project blueprint, Go backend skeleton, frontend app shell, database schema draft, and local development/deployment files.

internal/subsonic/service.go

@@ -0,0 +1,26 @@
+package subsonic
+
+type Envelope struct {
+	SubsonicResponse Response `json:"subsonic-response"`
+}
+
+type Response struct {
+	Status  string `json:"status"`
+	Version string `json:"version"`
+	Type    string `json:"type"`
+	Server  string `json:"serverVersion"`
+	OpenAPI bool   `json:"openSubsonic"`
+}
+
+func PingResponse() Envelope {
+	return Envelope{
+		SubsonicResponse: Response{
+			Status:  "ok",
+			Version: "1.16.1",
+			Type:    "temporserv",
+			Server:  "0.1.0",
+			OpenAPI: true,
+		},
+	}
+}
+