Fix UUID cast in task creation, add kind test manifests

- Fix parent_task_id NULLIF cast to UUID type in INSERT query
- Fix itoa helper to use strconv.Itoa
- Handle AddReaction errors gracefully in webhook handler
- Add hack/kind/ manifests for local testing with kind cluster

hack/kind/manifests/api-deployment.yaml

@@ -0,0 +1,61 @@
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: forgebot-api
+  namespace: forgebot
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: forgebot-api
+  template:
+    metadata:
+      labels:
+        app: forgebot-api
+    spec:
+      containers:
+        - name: api
+          image: forgebot-api:dev
+          imagePullPolicy: Never
+          ports:
+            - containerPort: 8000
+          env:
+            - name: LISTEN_ADDR
+              value: ":8000"
+            - name: DBHOST
+              value: postgres.forgebot.svc.cluster.local
+            - name: DBPORT
+              value: "5432"
+            - name: DBUSER
+              value: forgebot
+            - name: DBPASS
+              value: forgebot
+            - name: DBNAME
+              value: forgebot
+            - name: DBSSL
+              value: disable
+            - name: WEBHOOK_SECRET
+              value: ""
+            - name: GITEA_URL
+              value: "https://git.unkin.net"
+            - name: GITEA_TOKEN
+              value: ""
+          readinessProbe:
+            httpGet:
+              path: /health
+              port: 8000
+            initialDelaySeconds: 5
+            periodSeconds: 5
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: forgebot-api
+  namespace: forgebot
+spec:
+  selector:
+    app: forgebot-api
+  ports:
+    - port: 8000
+      targetPort: 8000