fix: offline sync basePath prefix and stable syncNow callback

- fetch URL: /api/incidents → /ims/api/incidents (basePath not auto-prepended in client fetch)
- replace syncing state guard with syncingRef to give syncNow a stable reference, preventing useEffect from re-registering the online listener on every sync cycle
- keep syncing state for UI rendering only

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FFDuBhMKvoWjrWT3ZnGmmr

components/incidents/offline-sync.tsx

@@ -1,10 +1,11 @@
 'use client'
 
-import { useEffect, useState, useCallback } from 'react'
+import { useEffect, useState, useCallback, useRef } from 'react'
 
 export function OfflineSync() {
   const [pendingCount, setPendingCount] = useState(0)
   const [syncing, setSyncing] = useState(false)
+  const syncingRef = useRef(false)
 
   async function checkPending() {
     const { getPendingCount } = await import('@/lib/offline/db')
@@ -12,7 +13,8 @@ export function OfflineSync() {
   }
 
   const syncNow = useCallback(async () => {
-    if (syncing) return
+    if (syncingRef.current) return
+    syncingRef.current = true
     setSyncing(true)
     try {
       const { getPendingReports, removePendingReport } = await import('@/lib/offline/db')
@@ -27,7 +29,7 @@ export function OfflineSync() {
         if (report.medical_status) fd.append('medical_status', report.medical_status)
 
         try {
-          const res = await fetch('/api/incidents', { method: 'POST', body: fd })
+          const res = await fetch('/ims/api/incidents', { method: 'POST', body: fd })
           if (res.ok && report.id != null) {
             await removePendingReport(report.id)
           }
@@ -36,10 +38,11 @@ export function OfflineSync() {
         }
       }
     } finally {
+      syncingRef.current = false
       await checkPending()
       setSyncing(false)
     }
-  }, [syncing])
+  }, [])
 
   useEffect(() => {
     // eslint-disable-next-line react-hooks/set-state-in-effect