fix: use pointer instead of payload in sessionStorage to prevent QuotaExceededError

Instead of storing full workflow JSON in sessionStorage (which can hit
quota on mobile), store only a small pointer to the draft path. The
actual workflow data lives in the draft store which has LRU eviction.

Loading priority:
1. SessionStorage pointer -> draft store
2. Preferred path -> draft store
3. Most recent draft (fallback)
4. Legacy sessionStorage payload (backward compat, remove after 2026-07-15)
5. Legacy localStorage payload (backward compat, remove after 2026-07-15)

This maintains duplicate-tab support while eliminating the quota issue.

Amp-Thread-ID: https://ampcode.com/threads/T-019bc597-fbea-778a-ae15-92061b3d0812
Co-authored-by: Amp <amp@ampcode.com>

src/platform/workflow/persistence/composables/useWorkflowPersistence.ts

@@ -81,27 +81,12 @@ export function useWorkflowPersistence() {
       return
     }
 
+    // Store pointer in sessionStorage for duplicate-tab support (small, won't hit quota)
+    // The actual workflow data is stored in the draft store which has eviction
     try {
-      localStorage.setItem('workflow', workflowJson)
-      if (api.clientId) {
-        sessionStorage.setItem(`workflow:${api.clientId}`, workflowJson)
-      }
-    } catch (error) {
-      // Only log our own keys and aggregate stats
-      const ourKeys = Object.keys(sessionStorage).filter(
-        (key) => key.startsWith('workflow:') || key === 'workflow'
-      )
-      console.error('QuotaExceededError details:', {
-        workflowSizeKB: Math.round(workflowJson.length / 1024),
-        totalStorageItems: Object.keys(sessionStorage).length,
-        ourWorkflowKeys: ourKeys.length,
-        ourWorkflowSizes: ourKeys.map((key) => ({
-          key,
-          sizeKB: Math.round(sessionStorage[key].length / 1024)
-        })),
-        error: error instanceof Error ? error.message : String(error)
-      })
-      throw error
+      sessionStorage.setItem('Comfy.Workflow.ActivePath', workflowPath)
+    } catch {
+      // Ignore - pointer is best-effort
     }
 
     lastSavedJsonByPath.value[workflowPath] = workflowJson

src/platform/workflow/persistence/stores/workflowDraftStore.ts

@@ -124,17 +124,26 @@ export const useWorkflowDraftStore = defineStore('workflowDraft', () => {
       fallbackToLatestDraft = false
     } = options
 
+    // 1. Try sessionStorage pointer (for duplicate-tab support)
+    const sessionPath = sessionStorage.getItem('Comfy.Workflow.ActivePath')
+    if (sessionPath && (await loadDraft(sessionPath))) {
+      return true
+    }
+
+    // 2. Try preferred path from caller
     if (preferredPath && (await loadDraft(preferredPath))) {
       return true
     }
 
-    if (!preferredPath && fallbackToLatestDraft) {
+    // 3. Fall back to most recent draft
+    if (fallbackToLatestDraft) {
       const fallbackPath = mostRecentDraft.value
       if (fallbackPath && (await loadDraft(fallbackPath))) {
         return true
       }
     }
 
+    // 4. Legacy fallback: sessionStorage payload (remove after 2026-07-15)
     const clientId = api.initialClientId ?? api.clientId
     if (clientId) {
       const sessionPayload = sessionStorage.getItem(`workflow:${clientId}`)
@@ -143,6 +152,7 @@ export const useWorkflowDraftStore = defineStore('workflowDraft', () => {
       }
     }
 
+    // 5. Legacy fallback: localStorage payload (remove after 2026-07-15)
     const localPayload = localStorage.getItem('workflow')
     return await tryLoadGraph(localPayload, workflowName)
   }