refactor(inbox): derive from snapshot; delete getInbox IPC chain

Sibling refactor to the sidebar-badges cleanup. The inbox aggregates
five item categories (pending approvals, failed runs, budget warnings,
blocked/review tasks, unread company/incident/urgent messages) — every
row is already in `ProfileSnapshot`. The server-side `getInbox`
aggregation (180 lines of SQL + projection) was a redundant second
path.

New: `src/shared/inbox-items.ts::deriveInboxItems(snapshot, companyId)`
produces the same InboxItem[] shape with the same severity ordering
and 24h failed-run window. Pure function, no IPC, no state.

Deleted:
- database/company-crud.ts::getInbox (180-line aggregation)
- database-base.ts::getInbox pass-through
- ipc-core-read-handlers.ts: handler
- preload/index.ts: bridge binding
- shared/contracts/channels.ts: channel name
- shared/contracts/desktop-api/companies.ts: API signature
- state/slices/company.ts: `inboxItems` field, `setInboxItems` action
- useDataLoader.ts: both getInbox call sites (initial snapshot load
  and section-change effect)
- useCompanyController.ts: inbox reset on company switch

OperationsSections now computes `inboxItems` via `useMemo` off the
current snapshot + company id. The snapshot is already company-scoped
at the main/database/snapshot.ts layer when `currentCompanyId` is
non-null; the derivation re-filters defensively so the function works
correctly even for unscoped snapshots.

Tests: 603/603 green. No new tests added — the derivation is a pure
function whose shape is exercised end-to-end by the existing Inbox
component integration.

src/renderer/hooks/useCompanyController.ts

@@ -35,7 +35,6 @@ export function useCompanyController() {
   const clearCompanyScopedUiState = useCallback(() => {
     const store = useAppStore.getState();
     store.clearCompanyScopedSelections();
-    store.setInboxItems([]);
     store.setCompanyMetrics(null);
     store.setStandupReport(null);
     store.setSocialAccounts([]);

src/renderer/hooks/useDataLoader.ts

@@ -24,8 +24,6 @@ export function useDataLoader(
       if (!currentSelectedConnectorId && next.connectors[0]) store.setSelectedConnectorId(next.connectors[0].id);
       if (!currentSelectedRunId && next.runs[0]) store.setSelectedRunId(next.runs[0].id);
       if (next.currentCompanyId) {
-        const inboxResult = await window.agentCompany.getInbox(next.currentCompanyId);
-        if (inboxResult.ok) store.setInboxItems(inboxResult.data);
         store.setSocialAccounts(next.socialAccounts?.filter((a) => a.companyId === next.currentCompanyId) ?? []);
         const browserActionResult = await window.agentCompany.listBrowserActions({ companyId: next.currentCompanyId, limit: 50 });
         if (browserActionResult.ok) {
@@ -50,12 +48,6 @@ export function useDataLoader(
     let cancelled = false;
     const store = useAppStore.getState();
 
-    if (section === "inbox") {
-      void window.agentCompany.getInbox(companyId).then((result) => {
-        if (!cancelled && result.ok) store.setInboxItems(result.data);
-      });
-    }
-
     if (section === "performance") {
       void window.agentCompany.getCompanyMetrics({ companyId, days: 30 }).then((result) => {
         if (!cancelled && result.ok) store.setCompanyMetrics(result.data);

src/renderer/state/slices/company.ts

@@ -4,17 +4,17 @@ import type {
   AgentRecord,
   ApprovalRecord,
   CompanyMetrics,
-  InboxItem,
   ProfileSnapshot,
   RunRecord,
   StandupReport,
   TaskRecord,
 } from "@shared/types";
 
-// Sidebar badge counts live in the renderer — derived from the
-// snapshot on every read via `deriveSidebarBadges` rather than cached
-// on this slice. One source of truth is the snapshot; adding a
-// separate `badges` field here is what let the counters drift.
+// Sidebar badge counts and inbox items both live in the renderer —
+// derived on every read from the snapshot (see `@shared/sidebar-badges`
+// and `@shared/inbox-items`). The snapshot is the only source of
+// truth; caching a separate `badges` or `inboxItems` field on this
+// slice is what let the counters drift against the rendered content.
 export interface CompanySlice {
   snapshot: ProfileSnapshot | null;
   /**
@@ -26,12 +26,10 @@ export interface CompanySlice {
   snapshotRevision: number;
   companyMetrics: CompanyMetrics | null;
   standupReport: StandupReport | null;
-  inboxItems: InboxItem[];
   error: string | null;
   setSnapshot: (snapshot: ProfileSnapshot | null) => void;
   setCompanyMetrics: (metrics: CompanyMetrics | null) => void;
   setStandupReport: (report: StandupReport | null) => void;
-  setInboxItems: (items: InboxItem[]) => void;
   setError: (error: string | null) => void;
   refreshSnapshot: () => Promise<void>;
   patchTask: (task: TaskRecord) => void;
@@ -54,7 +52,6 @@ export const createCompanySlice: StateCreator<
   snapshotRevision: 0,
   companyMetrics: null,
   standupReport: null,
-  inboxItems: [],
   error: null,
   setSnapshot: (snapshot) =>
     set((state) => {
@@ -69,10 +66,6 @@ export const createCompanySlice: StateCreator<
     set((state) => {
       state.standupReport = report;
     }),
-  setInboxItems: (items) =>
-    set((state) => {
-      state.inboxItems = items;
-    }),
   setError: (error) =>
     set((state) => {
       state.error = error;

src/renderer/views/sections/OperationsSections.tsx

@@ -1,4 +1,6 @@
+import { useMemo } from "react";
 import type { SectionId } from "@shared/types";
+import { deriveInboxItems } from "@shared/inbox-items";
 import { Inbox } from "../../components/inbox/Inbox";
 import { StandupView } from "../../components/inbox/StandupView";
 import { PerformanceView } from "../../components/inbox/PerformanceView";
@@ -47,7 +49,10 @@ export function OperationsSections({ section }: OperationsSectionsProps) {
   } = useSectionContext();
   const { refresh, openPathWithFeedback, setError } = useAppActions();
 
-  const inboxItems = useAppStore((s) => s.inboxItems);
+  const inboxItems = useMemo(
+    () => (snapshot ? deriveInboxItems(snapshot, currentCompany?.id ?? null) : []),
+    [snapshot, currentCompany?.id],
+  );
   const companyMetrics = useAppStore((s) => s.companyMetrics);
   const standupReport = useAppStore((s) => s.standupReport);
   const socialAccounts = useAppStore((s) => s.socialAccounts);