Initial commit: PilotVault multi-service project

Add API Server (Go/PocketBase), Web App (Go BFF + Vue), Fly App
(Flutter/DJI MSDK), Adobe Plugin, and Docker/Docker AIO deployment
configs. Design assets and build artifacts are gitignored.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

API Server/internal/api/respond.go

@@ -0,0 +1,29 @@
+package api
+
+import (
+	"encoding/json"
+	"log"
+	"net/http"
+)
+
+// writeJSON writes v as a JSON response with the given status code.
+func writeJSON(w http.ResponseWriter, status int, v any) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	if v == nil {
+		return
+	}
+	if err := json.NewEncoder(w).Encode(v); err != nil {
+		log.Printf("writeJSON: %v", err)
+	}
+}
+
+// errorBody is the standard error envelope.
+type errorBody struct {
+	Error string `json:"error"`
+}
+
+// writeError writes a JSON error response.
+func writeError(w http.ResponseWriter, status int, msg string) {
+	writeJSON(w, status, errorBody{Error: msg})
+}