Migrate from Gin to Echo framework and add comprehensive integration tests

Major changes:
- Migrate all handlers from Gin to Echo framework
- Add new apperrors, echohelpers, and validator packages
- Update middleware for Echo compatibility
- Add ArchivedHandler to task categorization chain (archived tasks go to cancelled_tasks column)
- Add 6 new integration tests:
  - RecurringTaskLifecycle: NextDueDate advancement for weekly/monthly tasks
  - MultiUserSharing: Complex sharing with user removal
  - TaskStateTransitions: All state transitions and kanban column changes
  - DateBoundaryEdgeCases: Threshold boundary testing
  - CascadeOperations: Residence deletion cascade effects
  - MultiUserOperations: Shared residence collaboration
- Add single-purpose repository functions for kanban columns (GetOverdueTasks, GetDueSoonTasks, etc.)
- Fix RemoveUser route param mismatch (userId -> user_id)
- Fix determineExpectedColumn helper to correctly prioritize in_progress over overdue

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/handlers/subscription_webhook_handler.go

@@ -14,7 +14,7 @@ import (
 	"strings"
 	"time"
 
-	"github.com/gin-gonic/gin"
+	"github.com/labstack/echo/v4"
 	"github.com/golang-jwt/jwt/v5"
 
 	"github.com/treytartt/casera-api/internal/config"
@@ -93,27 +93,24 @@ type AppleRenewalInfo struct {
 }
 
 // HandleAppleWebhook handles POST /api/subscription/webhook/apple/
-func (h *SubscriptionWebhookHandler) HandleAppleWebhook(c *gin.Context) {
-	body, err := io.ReadAll(c.Request.Body)
+func (h *SubscriptionWebhookHandler) HandleAppleWebhook(c echo.Context) error {
+	body, err := io.ReadAll(c.Request().Body)
 	if err != nil {
 		log.Printf("Apple Webhook: Failed to read body: %v", err)
-		c.JSON(http.StatusBadRequest, gin.H{"error": "failed to read request body"})
-		return
+		return c.JSON(http.StatusBadRequest, map[string]interface{}{"error": "failed to read request body"})
 	}
 
 	var payload AppleNotificationPayload
 	if err := json.Unmarshal(body, &payload); err != nil {
 		log.Printf("Apple Webhook: Failed to parse payload: %v", err)
-		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid payload"})
-		return
+		return c.JSON(http.StatusBadRequest, map[string]interface{}{"error": "invalid payload"})
 	}
 
 	// Decode and verify the signed payload (JWS)
 	notification, err := h.decodeAppleSignedPayload(payload.SignedPayload)
 	if err != nil {
 		log.Printf("Apple Webhook: Failed to decode signed payload: %v", err)
-		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid signed payload"})
-		return
+		return c.JSON(http.StatusBadRequest, map[string]interface{}{"error": "invalid signed payload"})
 	}
 
 	log.Printf("Apple Webhook: Received %s (subtype: %s) for bundle %s",
@@ -125,8 +122,7 @@ func (h *SubscriptionWebhookHandler) HandleAppleWebhook(c *gin.Context) {
 		if notification.Data.BundleID != cfg.AppleIAP.BundleID {
 			log.Printf("Apple Webhook: Bundle ID mismatch: got %s, expected %s",
 				notification.Data.BundleID, cfg.AppleIAP.BundleID)
-			c.JSON(http.StatusBadRequest, gin.H{"error": "bundle ID mismatch"})
-			return
+			return c.JSON(http.StatusBadRequest, map[string]interface{}{"error": "bundle ID mismatch"})
 		}
 	}
 
@@ -134,8 +130,7 @@ func (h *SubscriptionWebhookHandler) HandleAppleWebhook(c *gin.Context) {
 	transactionInfo, err := h.decodeAppleTransaction(notification.Data.SignedTransactionInfo)
 	if err != nil {
 		log.Printf("Apple Webhook: Failed to decode transaction: %v", err)
-		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid transaction info"})
-		return
+		return c.JSON(http.StatusBadRequest, map[string]interface{}{"error": "invalid transaction info"})
 	}
 
 	// Decode renewal info if present
@@ -151,7 +146,7 @@ func (h *SubscriptionWebhookHandler) HandleAppleWebhook(c *gin.Context) {
 	}
 
 	// Always return 200 OK to acknowledge receipt
-	c.JSON(http.StatusOK, gin.H{"status": "received"})
+	return c.JSON(http.StatusOK, map[string]interface{}{"status": "received"})
 }
 
 // decodeAppleSignedPayload decodes and verifies an Apple JWS payload
@@ -454,41 +449,36 @@ const (
 )
 
 // HandleGoogleWebhook handles POST /api/subscription/webhook/google/
-func (h *SubscriptionWebhookHandler) HandleGoogleWebhook(c *gin.Context) {
-	body, err := io.ReadAll(c.Request.Body)
+func (h *SubscriptionWebhookHandler) HandleGoogleWebhook(c echo.Context) error {
+	body, err := io.ReadAll(c.Request().Body)
 	if err != nil {
 		log.Printf("Google Webhook: Failed to read body: %v", err)
-		c.JSON(http.StatusBadRequest, gin.H{"error": "failed to read request body"})
-		return
+		return c.JSON(http.StatusBadRequest, map[string]interface{}{"error": "failed to read request body"})
 	}
 
 	var notification GoogleNotification
 	if err := json.Unmarshal(body, &notification); err != nil {
 		log.Printf("Google Webhook: Failed to parse notification: %v", err)
-		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid notification"})
-		return
+		return c.JSON(http.StatusBadRequest, map[string]interface{}{"error": "invalid notification"})
 	}
 
 	// Decode the base64 data
 	data, err := base64.StdEncoding.DecodeString(notification.Message.Data)
 	if err != nil {
 		log.Printf("Google Webhook: Failed to decode message data: %v", err)
-		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid message data"})
-		return
+		return c.JSON(http.StatusBadRequest, map[string]interface{}{"error": "invalid message data"})
 	}
 
 	var devNotification GoogleDeveloperNotification
 	if err := json.Unmarshal(data, &devNotification); err != nil {
 		log.Printf("Google Webhook: Failed to parse developer notification: %v", err)
-		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid developer notification"})
-		return
+		return c.JSON(http.StatusBadRequest, map[string]interface{}{"error": "invalid developer notification"})
 	}
 
 	// Handle test notification
 	if devNotification.TestNotification != nil {
 		log.Printf("Google Webhook: Received test notification")
-		c.JSON(http.StatusOK, gin.H{"status": "test received"})
-		return
+		return c.JSON(http.StatusOK, map[string]interface{}{"status": "test received"})
 	}
 
 	// Verify package name
@@ -497,8 +487,7 @@ func (h *SubscriptionWebhookHandler) HandleGoogleWebhook(c *gin.Context) {
 		if devNotification.PackageName != cfg.GoogleIAP.PackageName {
 			log.Printf("Google Webhook: Package name mismatch: got %s, expected %s",
 				devNotification.PackageName, cfg.GoogleIAP.PackageName)
-			c.JSON(http.StatusBadRequest, gin.H{"error": "package name mismatch"})
-			return
+			return c.JSON(http.StatusBadRequest, map[string]interface{}{"error": "package name mismatch"})
 		}
 	}
 
@@ -511,7 +500,7 @@ func (h *SubscriptionWebhookHandler) HandleGoogleWebhook(c *gin.Context) {
 	}
 
 	// Acknowledge the message
-	c.JSON(http.StatusOK, gin.H{"status": "received"})
+	return c.JSON(http.StatusOK, map[string]interface{}{"status": "received"})
 }
 
 // processGoogleSubscriptionNotification handles Google subscription events
@@ -736,7 +725,7 @@ func (h *SubscriptionWebhookHandler) VerifyAppleSignature(signedPayload string)
 }
 
 // VerifyGooglePubSubToken verifies the Pub/Sub push token (if configured)
-func (h *SubscriptionWebhookHandler) VerifyGooglePubSubToken(c *gin.Context) bool {
+func (h *SubscriptionWebhookHandler) VerifyGooglePubSubToken(c echo.Context) bool {
 	// If you configured a push endpoint with authentication, verify here
 	// The token is typically in the Authorization header