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/monitoring/handler.go

@@ -8,7 +8,7 @@ import (
 	"sync"
 	"time"
 
-	"github.com/gin-gonic/gin"
+	"github.com/labstack/echo/v4"
 	"github.com/gorilla/websocket"
 	"github.com/rs/zerolog/log"
 )
@@ -38,11 +38,10 @@ func NewHandler(logBuffer *LogBuffer, statsStore *StatsStore) *Handler {
 
 // GetLogs returns filtered log entries
 // GET /api/admin/monitoring/logs
-func (h *Handler) GetLogs(c *gin.Context) {
+func (h *Handler) GetLogs(c echo.Context) error {
 	var filters LogFilters
-	if err := c.ShouldBindQuery(&filters); err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid filters"})
-		return
+	if err := c.Bind(&filters); err != nil {
+		return c.JSON(http.StatusBadRequest, map[string]interface{}{"error": "Invalid filters"})
 	}
 
 	limit := filters.GetLimit()
@@ -51,8 +50,7 @@ func (h *Handler) GetLogs(c *gin.Context) {
 	entries, err := h.logBuffer.GetRecent(limit * 2)
 	if err != nil {
 		log.Error().Err(err).Msg("Failed to get logs from buffer")
-		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to retrieve logs"})
-		return
+		return c.JSON(http.StatusInternalServerError, map[string]interface{}{"error": "Failed to retrieve logs"})
 	}
 
 	// Apply filters
@@ -83,7 +81,7 @@ func (h *Handler) GetLogs(c *gin.Context) {
 		}
 	}
 
-	c.JSON(http.StatusOK, gin.H{
+	return c.JSON(http.StatusOK, map[string]interface{}{
 		"logs":  filtered,
 		"total": len(filtered),
 	})
@@ -91,41 +89,38 @@ func (h *Handler) GetLogs(c *gin.Context) {
 
 // GetStats returns system statistics for all processes
 // GET /api/admin/monitoring/stats
-func (h *Handler) GetStats(c *gin.Context) {
+func (h *Handler) GetStats(c echo.Context) error {
 	allStats, err := h.statsStore.GetAllStats()
 	if err != nil {
 		log.Error().Err(err).Msg("Failed to get stats from store")
-		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to retrieve stats"})
-		return
+		return c.JSON(http.StatusInternalServerError, map[string]interface{}{"error": "Failed to retrieve stats"})
 	}
 
-	c.JSON(http.StatusOK, allStats)
+	return c.JSON(http.StatusOK, allStats)
 }
 
 // ClearLogs clears all logs from the buffer
 // DELETE /api/admin/monitoring/logs
-func (h *Handler) ClearLogs(c *gin.Context) {
+func (h *Handler) ClearLogs(c echo.Context) error {
 	if err := h.logBuffer.Clear(); err != nil {
 		log.Error().Err(err).Msg("Failed to clear logs")
-		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to clear logs"})
-		return
+		return c.JSON(http.StatusInternalServerError, map[string]interface{}{"error": "Failed to clear logs"})
 	}
 
-	c.JSON(http.StatusOK, gin.H{"message": "Logs cleared"})
+	return c.JSON(http.StatusOK, map[string]interface{}{"message": "Logs cleared"})
 }
 
 // WebSocket handles real-time log streaming
 // GET /api/admin/monitoring/ws
-func (h *Handler) WebSocket(c *gin.Context) {
-	conn, err := upgrader.Upgrade(c.Writer, c.Request, nil)
+func (h *Handler) WebSocket(c echo.Context) error {
+	conn, err := upgrader.Upgrade(c.Response().Writer, c.Request(), nil)
 	if err != nil {
 		log.Error().Err(err).Msg("Failed to upgrade WebSocket connection")
-		return
 	}
 	defer conn.Close()
 
 	// Create context that cancels when connection closes
-	ctx, cancel := context.WithCancel(c.Request.Context())
+	ctx, cancel := context.WithCancel(c.Request().Context())
 	defer cancel()
 
 	// Subscribe to Redis pubsub for logs
@@ -139,7 +134,6 @@ func (h *Handler) WebSocket(c *gin.Context) {
 			_, _, err := conn.ReadMessage()
 			if err != nil {
 				cancel()
-				return
 			}
 		}
 	}()
@@ -173,7 +167,6 @@ func (h *Handler) WebSocket(c *gin.Context) {
 
 			if err != nil {
 				log.Debug().Err(err).Msg("WebSocket write error")
-				return
 			}
 
 		case <-statsTicker.C:
@@ -181,7 +174,6 @@ func (h *Handler) WebSocket(c *gin.Context) {
 			h.sendStats(conn, &wsMu)
 
 		case <-ctx.Done():
-			return
 		}
 	}
 }
@@ -189,7 +181,6 @@ func (h *Handler) WebSocket(c *gin.Context) {
 func (h *Handler) sendStats(conn *websocket.Conn, mu *sync.Mutex) {
 	allStats, err := h.statsStore.GetAllStats()
 	if err != nil {
-		return
 	}
 
 	wsMsg := WSMessage{