diff --git a/docker/Dockerfile b/docker/Dockerfile
index d57b620..712fdda 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -69,5 +69,8 @@ EXPOSE 7600
 ENV PORT=7600
 ENV HOSTNAME="0.0.0.0"
 
+HEALTHCHECK --interval=30s --timeout=5s --start-period=30s --retries=3 \
+  CMD wget -qO- http://localhost:7600/api/health || exit 1
+
 # Run via entrypoint (migrate then start)
 CMD ["/app/docker-entrypoint.sh"]
diff --git a/src/app/(admin)/admin/settings/webhooks/page.tsx b/src/app/(admin)/admin/settings/webhooks/page.tsx
index 64a5b27..557dffc 100644
--- a/src/app/(admin)/admin/settings/webhooks/page.tsx
+++ b/src/app/(admin)/admin/settings/webhooks/page.tsx
@@ -210,11 +210,16 @@ export default function WebhooksPage() {
       return
     }
 
+    const filteredHeaders = formData.headers.filter((h) => h.key)
+    const headersRecord = filteredHeaders.length > 0
+      ? Object.fromEntries(filteredHeaders.map((h) => [h.key, h.value]))
+      : undefined
+
     const payload = {
       name: formData.name,
       url: formData.url,
       events: formData.events,
-      headers: formData.headers.filter((h) => h.key) as Record<string, string>[] | undefined,
+      headers: headersRecord,
       maxRetries: formData.maxRetries,
     }
 
diff --git a/src/server/routers/user.ts b/src/server/routers/user.ts
index 3b61923..71c3dfd 100644
--- a/src/server/routers/user.ts
+++ b/src/server/routers/user.ts
@@ -106,7 +106,7 @@ export const userRouter = router({
         notificationPreference: z.enum(['EMAIL', 'WHATSAPP', 'BOTH', 'NONE']).optional(),
         expertiseTags: z.array(z.string()).max(15).optional(),
         digestFrequency: z.enum(['none', 'daily', 'weekly']).optional(),
-        availabilityJson: z.any().optional(),
+        availabilityJson: z.array(z.object({ start: z.string(), end: z.string() })).optional(),
         preferredWorkload: z.number().int().min(1).max(100).optional().nullable(),
       })
     )
@@ -539,7 +539,7 @@ export const userRouter = router({
         status: z.enum(['NONE', 'INVITED', 'ACTIVE', 'SUSPENDED']).optional(),
         expertiseTags: z.array(z.string()).optional(),
         maxAssignments: z.number().int().min(1).max(100).optional().nullable(),
-        availabilityJson: z.any().optional(),
+        availabilityJson: z.array(z.object({ start: z.string(), end: z.string() })).optional(),
         preferredWorkload: z.number().int().min(1).max(100).optional().nullable(),
       })
     )
diff --git a/src/server/routers/webhook.ts b/src/server/routers/webhook.ts
index 0b9b77d..a95feab 100644
--- a/src/server/routers/webhook.ts
+++ b/src/server/routers/webhook.ts
@@ -81,7 +81,7 @@ export const webhookRouter = router({
         name: z.string().min(1).max(200),
         url: z.string().url(),
         events: z.array(z.string()).min(1),
-        headers: z.any().optional(),
+        headers: z.record(z.string()).optional(),
         maxRetries: z.number().int().min(0).max(10).default(3),
       })
     )
@@ -126,7 +126,7 @@ export const webhookRouter = router({
         name: z.string().min(1).max(200).optional(),
         url: z.string().url().optional(),
         events: z.array(z.string()).min(1).optional(),
-        headers: z.any().optional(),
+        headers: z.record(z.string()).optional(),
         isActive: z.boolean().optional(),
         maxRetries: z.number().int().min(0).max(10).optional(),
       })