feat(backend): update scheduling handlers

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

backend/handlers/scheduling/default-hours.go

@@ -9,15 +9,16 @@ import (
 	"time"
 
 	"crussell/db"
+	"crussell/internal/validators"
 	"crussell/mw"
 	"log"
 )
 
 // --- Types ---
 type DefaultHours struct {
-	Weekday   int    `json:"weekday"`
-	StartTime string `json:"startTime"`
-	EndTime   string `json:"endTime"`
+	Weekday   int    `json:"weekday" validate:"gte=0,lte=6"`
+	StartTime string `json:"startTime" validate:"required"`
+	EndTime   string `json:"endTime" validate:"required"`
 	IsOpen    bool   `json:"isOpen"`
 }
 
@@ -63,6 +64,16 @@ func UpdateDefaultHours(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	for _, h := range hours {
+		if err := validators.Validate.Struct(&h); err != nil {
+			http.Error(w, err.Error(), http.StatusBadRequest)
+			return
+		}
+	}
+
+	// M8
+	// L5
+
 	for _, h := range hours {
 		if !isValidTime15Min(h.StartTime) {
 			http.Error(w, "start_time must be in 15-minute intervals (00, 15, 30, 45)", http.StatusBadRequest)
@@ -425,6 +436,7 @@ func GetAvailableHours(w http.ResponseWriter, r *http.Request) {
 			) sub), 0) AS total_duration
 		FROM bookings b
 		WHERE b.start_time >= $1 AND b.start_time <= $2
+		  AND b.status NOT IN ('client_cancelled', 'we_cancelled', 'no_show', 'pending_release', 'deposit_lapsed')
 		ORDER BY b.start_time
 	`, start, end)