fix(api): allow forking up to concurrency limit from named snapshot

Unlike /sandboxes/{id}/fork where the source sandbox occupies a slot,
/snapshots/{id}/fork has no running source sandbox. Using >= rejected
count == limit even when all slots were free. Changed to > so users can
fork up to their full concurrency limit in one request.

Author: adababys

packages/api/internal/handlers/snapshot_fork.go

@@ -76,8 +76,8 @@ func (a *APIStore) PostSnapshotsSnapshotIDFork(c *gin.Context, rawSnapshotID api
 		return
 	}
 
-	if int64(forkCount) >= teamInfo.Limits.SandboxConcurrency {
-		a.sendAPIStoreError(c, http.StatusBadRequest, fmt.Sprintf("Count must be lower than the maximum number of concurrent sandboxes (%d)", teamInfo.Limits.SandboxConcurrency))
+	if int64(forkCount) > teamInfo.Limits.SandboxConcurrency {
+		a.sendAPIStoreError(c, http.StatusBadRequest, fmt.Sprintf("Count must not exceed the maximum number of concurrent sandboxes (%d)", teamInfo.Limits.SandboxConcurrency))
 		return
 	}