Reduce handler request boilerplate

- Add session.Attach to reuse per-request sessions across middleware and ghome handlers
- Make Session finalize/abort paths idempotent to avoid duplicate commit or rollback work
- Move request_data parsing helper to internal/utils
- Expand ParseRequestData usage across api, download, unit, live, multiunit, and subscenario handlers
- Extract download package metadata into internal/handler/download/types.go
- Return explicit errors from selected session lookup helpers and update callers
- Make api action handlers return errors directly instead of calling ss.CheckErr in nested layers

Signed-off-by: Sean Du <do4suki@gmail.com>

internal/handler/ghome/account/active.go

@@ -9,7 +9,7 @@ import (
 )
 
 func active(ctx *gin.Context) {
-	ss := session.New(ctx)
+	ss := session.Attach(ctx)
 	defer ss.Finalize()
 
 	ss.Respond(ghomeschema.ActiveResp{

internal/handler/ghome/account/initialize.go

@@ -13,7 +13,7 @@ import (
 )
 
 func initialize(ctx *gin.Context) {
-	ss := session.New(ctx)
+	ss := session.Attach(ctx)
 	defer ss.Finalize()
 
 	initData := ghomeschema.InitializeData{

internal/handler/ghome/account/login.go

@@ -33,7 +33,7 @@ const (
 )
 
 func login(ctx *gin.Context) {
-	ss := session.New(ctx)
+	ss := session.Attach(ctx)
 	defer ss.Finalize()
 
 	data, err := ctx.GetRawData()

internal/handler/ghome/account/loginauto.go

@@ -15,7 +15,7 @@ import (
 )
 
 func loginAuto(ctx *gin.Context) {
-	ss := session.New(ctx)
+	ss := session.Attach(ctx)
 	defer ss.Finalize()
 
 	data, err := ctx.GetRawData()

internal/handler/ghome/account/reportrole.go

@@ -11,7 +11,7 @@ import (
 )
 
 func reportRole(ctx *gin.Context) {
-	ss := session.New(ctx)
+	ss := session.Attach(ctx)
 	defer ss.Finalize()
 
 	randKey, err := ss.Get3DESRandKey()

internal/handler/ghome/basic/getcode.go

@@ -10,7 +10,7 @@ import (
 )
 
 func getCode(ctx *gin.Context) {
-	ss := session.New(ctx)
+	ss := session.Attach(ctx)
 	defer ss.Finalize()
 
 	codeArray := `{"codeArray":[{"btntext":"好的","code":"-10264022","msg_from":2,"text":"","title":"短信验证码被阻止","type":1},{"btntext":"","code":"-10869623","msg_from":2,"text":"","title":"网络连接失败，无法一键登录","type":2},{"btntext":"","code":"10298300","msg_from":2,"text":"","title":"","type":3},{"btntext":"","code":"10298311","msg_from":2,"text":"","title":"","type":3},{"btntext":"","code":"10298312","msg_from":2,"text":"","title":"","type":3},{"btntext":"","code":"10298313","msg_from":2,"text":"","title":"","type":1},{"btntext":"","code":"10298321","msg_from":2,"text":"","title":"","type":3},{"btntext":"","code":"10298322","msg_from":2,"text":"","title":"","type":3}],"codeVersion":"1.0.5"}`

internal/handler/ghome/basic/getproductlist.go

@@ -9,7 +9,7 @@ import (
 )
 
 func getProductList(ctx *gin.Context) {
-	ss := session.New(ctx)
+	ss := session.Attach(ctx)
 	defer ss.Finalize()
 
 	getProductListData := ghomeschema.GetProductListData{

internal/handler/ghome/basic/handshake.go

@@ -17,7 +17,7 @@ import (
 )
 
 func handshake(ctx *gin.Context) {
-	ss := session.New(ctx)
+	ss := session.Attach(ctx)
 	defer ss.Finalize()
 
 	data, err := ctx.GetRawData()

internal/handler/ghome/basic/loginarea.go

@@ -9,7 +9,7 @@ import (
 )
 
 func loginArea(ctx *gin.Context) {
-	ss := session.New(ctx)
+	ss := session.Attach(ctx)
 	defer ss.Finalize()
 
 	ss.Respond(ghomeschema.LoginAreaResp{

internal/handler/ghome/basic/publickey.go

@@ -13,7 +13,7 @@ import (
 )
 
 func publicKey(ctx *gin.Context) {
-	ss := session.New(ctx)
+	ss := session.Attach(ctx)
 	defer ss.Finalize()
 
 	publicKeyCode := 0

internal/handler/ghome/guest/status.go

@@ -9,7 +9,7 @@ import (
 )
 
 func status(ctx *gin.Context) {
-	ss := session.New(ctx)
+	ss := session.Attach(ctx)
 	defer ss.Finalize()
 
 	ss.Respond(ghomeschema.GuestStatusResp{

internal/handler/ghome/misc/agreement.go

@@ -9,7 +9,7 @@ import (
 )
 
 func agreement(ctx *gin.Context) {
-	ss := session.New(ctx)
+	ss := session.Attach(ctx)
 	defer ss.Finalize()
 
 	ss.Respond(ghomeschema.AgreementResp{

internal/handler/ghome/misc/integration.go

@@ -9,7 +9,7 @@ import (
 )
 
 func appReport(ctx *gin.Context) {
-	ss := session.New(ctx)
+	ss := session.Attach(ctx)
 	defer ss.Finalize()
 
 	ss.Respond(ghomeschema.AppReportResp{