Declare app version per channel and fix Android live updates

- Pin the radiantwave input to tag 1.8 and add channel.appVersion; override the package version so pure builds bake 1.8 instead of RadiantWave's 0.1.0 default.

- radiantwaveUpdaterModule gains a manifestFile arg; Raspberry Pi polls aarch64-manifest.json.

- Launch the rotated/Android kiosk through /var/lib/radiantwave/current so the live updater actually applies.

- Allow unfree in the RPi builder to match x86 and drop the impure NIXPKGS_ALLOW_UNFREE dependency.

flake.lock

@@ -220,16 +220,16 @@
         "nixpkgs": "nixpkgs_3"
       },
       "locked": {
-        "lastModified": 1789157302,
-        "narHash": "sha256-9wOHFEkFd7Lz1cJoUWBksgzTB+RP6sdtiF3hpyOrnQY=",
-        "ref": "main",
-        "rev": "a043ec84d8c421f6fc2abb064da2836449010868",
-        "revCount": 64,
+        "lastModified": 1790803867,
+        "narHash": "sha256-HRGQQlmn/kCsZIq1wBMFaW6q1xfSvwPhUS5CpG1mm+Q=",
+        "ref": "refs/tags/1.8",
+        "rev": "34c72b51ddc3da8d46d994e787ffd1f8e8dda77c",
+        "revCount": 85,
         "type": "git",
         "url": "https://gitea.radiantwavetech.com/RadiantWaveTech/radiantwave.git"
       },
       "original": {
-        "ref": "main",
+        "ref": "refs/tags/1.8",
         "type": "git",
         "url": "https://gitea.radiantwavetech.com/RadiantWaveTech/radiantwave.git"
       }