refactor: centralize thread filter value domains

Consolidate filter value definitions in agents-view-thread-filters
and use them in Zod schema validation to ensure consistent,
persistent serialization of filter state.

src/main/runtime/rpc/methods/client-ui-schemas.ts

@@ -3,6 +3,10 @@ import {
   isFeatureInteractionId,
   type FeatureInteractionId
 } from '../../../../shared/feature-interactions'
+import {
+  ACTIVITY_GROUP_BY_VALUES,
+  THREAD_READ_FILTER_VALUES
+} from '../../../../shared/agents-view-thread-filters'
 import { isFeatureTipId } from '../../../../shared/feature-tips'
 import { isReleaseChannel, type ReleaseChannel } from '../../../../shared/release-channel'
 import {
@@ -126,8 +130,8 @@ const UiUpdateFields = z
     agentsFilterRepoIds: StringArray.optional(),
     agentsShowChildAgents: z.boolean().optional(),
     agentsCompactMode: z.boolean().optional(),
-    agentsReadFilter: z.enum(['all', 'unread']).optional(),
-    agentsGroupBy: z.enum(['none', 'status', 'project', 'worktree', 'agent']).optional(),
+    agentsReadFilter: z.enum(THREAD_READ_FILTER_VALUES).optional(),
+    agentsGroupBy: z.enum(ACTIVITY_GROUP_BY_VALUES).optional(),
     workspaceHostOrder: z.array(z.string()).optional(),
     automationHostFilter: z
       .union([

src/shared/ui-chrome-types.ts

@@ -49,8 +49,9 @@ export type WorktreeCardMode = 'Default' | 'Compact'
 
 export type AgentActivityDisplayMode = 'compact' | 'full'
 
-export type ThreadReadFilter = 'all' | 'unread'
-export type ActivityGroupBy = 'none' | 'status' | 'project' | 'worktree' | 'agent'
+// Re-exported so existing importers keep one home for UI chrome types; the
+// value domain lives with the normalizers that police it.
+export type { ActivityGroupBy, ThreadReadFilter } from './agents-view-thread-filters'
 
 export type StatusBarItem =
   | 'claude'