feat(build): set deterministic artifact file names

Standardize generated installer/artifact file names across build
targets by adding explicit artifactName patterns in package.json.
Add a general artifactName at the top-level build config, ensure
linux targets (snap/deb/rpm) carry the same pattern, and set a
Windows-specific artifactName for win and nsis outputs that includes
the platform and arch.

This makes build outputs predictable for CI, releases, and automated
upload tooling by embedding name, version, OS, arch, and extension in
artifact filenames.

package.json

@@ -22,6 +22,7 @@
     "build": {
         "appId": "com.fourgray.iptvnator",
         "productName": "IPTVnator",
+        "artifactName": "${name}-${version}-${os}-${arch}.${ext}",
         "mac": {
             "target": {
                 "target": "dmg",
@@ -44,7 +45,8 @@
                 "Snap",
                 "deb",
                 "rpm"
-            ]
+            ],
+            "artifactName": "${name}-${version}-${os}-${arch}.${ext}"
         },
         "win": {
             "compression": "maximum",
@@ -56,7 +58,11 @@
                         "x64"
                     ]
                 }
-            ]
+            ],
+            "artifactName": "${name}-${version}-windows-${arch}-setup.${ext}"
+        },
+        "nsis": {
+            "artifactName": "${name}-${version}-windows-${arch}-setup.${ext}"
         }
     },
     "scripts": {