[fix](trx-frontend-http): close IIFE before bandplan strip declarations

The spectrum floor/gamma IIFE (line 11507) was missing its closing
`})();`, causing all bandplan strip variables and functions to be
trapped inside the IIFE scope. This made `bandplanRegion`,
`updateBandplanStrip`, and `_bandplanServerDefaultApplied` invisible
to the rest of the file, throwing ReferenceErrors that crashed
`render()` before the frequency display update could run — leaving
the frequency input stuck at its initial "--" placeholder.

https://claude.ai/code/session_01RgKhusmnk7AHEJqn1KHffU
Signed-off-by: Claude <noreply@anthropic.com>

src/trx-client/trx-frontend/trx-frontend-http/assets/web/app.js

@@ -11577,6 +11577,7 @@ if (spectrumCenterRightBtn) {
       if (lastSpectrumData) scheduleSpectrumDraw();
     });
   }
+})();
 
 // ── Bandplan strip ──────────────────────────────────────────────────────────
 let bandplanData = null;
@@ -11787,4 +11788,3 @@ function updateBandplanStrip(range) {
     lbl.style.display = (frac < -0.1 || frac > 1.05) ? "none" : "";
   });
 }
-})();