feat: add main features

Agents for developpement added + frontend add + backend added. Git viewer created + agent and template creator + layout and project creator

frontend/src/features/layout/index.ts

@@ -0,0 +1,15 @@
+/** Layout feature (L4): recursive spreadsheet-like terminal grid. */
+
+export { LayoutGrid } from "./LayoutGrid";
+export { useLayout, type LayoutViewModel } from "./useLayout";
+export { useLayouts, type LayoutsViewModel } from "./useLayouts";
+export { LayoutTabs } from "./LayoutTabs";
+export {
+  applyOperation,
+  leaves,
+  newId,
+  normalizeWeights,
+  resizeAdjacent,
+  singleLeafTree,
+  splitOp,
+} from "./layout";