Bottom-bar module picker routes

- Add GET/POST /settings/bottombar to choose the pinned module.

src/backend/backend.js

@@ -7887,6 +7887,15 @@ router
     saveConfig(cfg);
     ctx.redirect(`/modules`);
   })
+  .get("/settings/bottombar", async (ctx) => {
+    ctx.body = require("../views/main_views").bottomBarPickerView();
+  })
+  .post("/settings/bottombar", koaBody(), async (ctx) => {
+    const cfg = getConfig();
+    cfg.bottomBarPin = String(ctx.request.body.pin || '').trim();
+    saveConfig(cfg);
+    ctx.redirect('/activity');
+  })
   .post("/settings/ai", koaBody(), async (ctx) => {
     const aiPrompt = String(ctx.request.body.ai_prompt || "").trim();
     if (aiPrompt.length > 128) { sendErrorPage(ctx, "Prompt too long. Must be 128 characters or fewer.", { status: 400 }); return; }