refactor(renderer): dismantle useAppController 47-prop god-hook

Sections now subscribe directly to the Zustand store via useSectionContext
(shared data derivation) and useAppStore fine-grained selectors. Delete
useAppController, useExecutionController, useOrganizationController, and
useCommunicationController; the three domain forwarders held no logic
beyond re-exporting store slices.

SectionContentView becomes a 50-line layout dispatcher taking only
{section, error, pageTransition}; cross-domain run actions (startRun /
cancelRun) move into App.tsx and are exposed to sections through a new
AppActionsContext alongside refresh / setError / openPathWithFeedback.
App.tsx now calls useUIController + useCompanyController directly and
composes palette + navigation plumbing itself.

src/renderer/hooks/useSectionContext.ts

@@ -0,0 +1,40 @@
+import { useMemo } from "react";
+import type { CompanyRecord } from "@shared/types";
+import { useAppStore } from "../state/store";
+import { useCompanyData } from "./useCompanyData";
+
+/**
+ * Shared data context for section views. Subscribes to the Zustand store
+ * for snapshot + current company, derives per-company collections and
+ * currently-selected entities via useCompanyData.
+ *
+ * Sections call this hook directly instead of receiving 30+ props through
+ * SectionContentView.
+ */
+export function useSectionContext() {
+  const snapshot = useAppStore((s) => s.snapshot);
+
+  const currentCompany = useMemo<CompanyRecord | null>(() => {
+    if (!snapshot) return null;
+    return (
+      snapshot.companies.find((company) => company.id === snapshot.currentCompanyId) ??
+      snapshot.companies[0] ??
+      null
+    );
+  }, [snapshot]);
+
+  const companyData = useCompanyData(snapshot, currentCompany);
+
+  const selectedConnectorId = useAppStore((s) => s.selectedConnectorId);
+  const selectedConnector =
+    snapshot?.connectors.find((connector) => connector.id === selectedConnectorId) ??
+    snapshot?.connectors[0] ??
+    null;
+
+  return {
+    snapshot,
+    currentCompany,
+    selectedConnector,
+    ...companyData,
+  };
+}