fix(ci): bump only TeleUploader flake version, not Bun overlay

prepare.mjs previously replaced the FIRST version="X" string in flake.nix,
which is the Bun overlay override (line ~17), not the TeleUploader package
version (pname = "teleuploader", line ~30). Store path derives from the
TeleUploader version, so the Bun override got clobbered to the app version
while the store path stayed at 1.1.1 -> deploy reused the old derivation and
the VPS profile never advanced.

Now prepare.mjs anchors on pname = "teleuploader" and bumps that block only,
leaving the Bun 1.3.14 override intact. Verified: flake.nix keeps
bun version=1.3.14, teleuploader version becomes the semver-version.
Also restores bun overlay version=1.3.14 (was overwritten to 1.2.0).

flake.nix

@@ -14,7 +14,7 @@
           overlays = [
             (self: super: {
               bun = super.bun.overrideAttrs (old: rec {
-                version = "1.2.0";
+                version = "1.3.14";
                 src = super.fetchzip {
                   url = "https://github.com/oven-sh/bun/releases/download/bun-v1.3.14/bun-linux-x64.zip";
                   sha256 = "sha256:189kasncnfpq6q37q3w80dv2a92w79w20x2x6hf1fbkir5gyvzlb";
@@ -27,7 +27,7 @@
         # TeleUploader package
         teleuploader = pkgs.stdenvNoCC.mkDerivation rec {
           pname = "teleuploader";
-          version = "1.1.1";
+          version = "1.2.0";
 
           src = ./.;