Read android args from config file on device

- allows use of more interesting args w/o risk of checking them in by mistake
- allows use of different args w/o rebuilding the app
- uses compiled in defaults if config file missing or broken

Example android-config.json:
```
{
  "args": [
    "--npub",
    "npub1h50pnxqw9jg7dhr906fvy4mze2yzawf895jhnc3p7qmljdugm6gsrurqev",
    "-c",
    "contacts",
    "-c",
    "notifications"
  ]
}
```

Install/update android-config.json with:
```
adb push android-config.json /sdcard/Android/data/com.damus.app/files/android-config.json
```

Using internal storage would be better but it seems hard to get the config file onto
the device ...

src/lib.rs

@@ -68,11 +68,66 @@ pub async fn android_main(app: AndroidApp) {
     let path = app.internal_data_path().expect("data path");
     let mut options = eframe::NativeOptions::default();
     options.renderer = eframe::Renderer::Wgpu;
+    // Clone `app` to use it both in the closure and later in the function
+    let app_clone_for_event_loop = app.clone();
     options.event_loop_builder = Some(Box::new(move |builder| {
-        builder.with_android_app(app);
+        builder.with_android_app(app_clone_for_event_loop);
     }));
 
-    let args = vec![
+    let app_args = get_app_args(app);
+
+    let _res = eframe::run_native(
+        "Damus NoteDeck",
+        options,
+        Box::new(move |cc| Ok(Box::new(Damus::new(cc, path, app_args)))),
+    );
+}
+
+#[cfg(target_os = "android")]
+use serde_json::Value;
+#[cfg(target_os = "android")]
+use std::fs;
+#[cfg(target_os = "android")]
+use std::path::PathBuf;
+
+/*
+Read args from a config file:
+- allows use of more interesting args w/o risk of checking them in by mistake
+- allows use of different args w/o rebuilding the app
+- uses compiled in defaults if config file missing or broken
+
+Example android-config.json:
+```
+{
+  "args": [
+    "--npub",
+    "npub1h50pnxqw9jg7dhr906fvy4mze2yzawf895jhnc3p7qmljdugm6gsrurqev",
+    "-c",
+    "contacts",
+    "-c",
+    "notifications"
+  ]
+}
+```
+
+Install/update android-config.json with:
+```
+adb push android-config.json /sdcard/Android/data/com.damus.app/files/android-config.json
+```
+
+Using internal storage would be better but it seems hard to get the config file onto
+the device ...
+*/
+
+#[cfg(target_os = "android")]
+fn get_app_args(app: AndroidApp) -> Vec<String> {
+    let external_data_path: PathBuf = app
+        .external_data_path()
+        .expect("external data path")
+        .to_path_buf();
+    let config_file = external_data_path.join("android-config.json");
+
+    let default_args = vec![
         "--pub",
         "32e1827635450ebb3c5a7d12c1f8e7b2b514439ac10a67eef3d9fd9c5c68e245",
         "-c",
@@ -86,9 +141,20 @@ pub async fn android_main(app: AndroidApp) {
     .map(|s| s.to_string())
     .collect();
 
-    let _res = eframe::run_native(
-        "Damus NoteDeck",
-        options,
-        Box::new(move |cc| Ok(Box::new(Damus::new(cc, path, args)))),
-    );
+    if config_file.exists() {
+        if let Ok(config_contents) = fs::read_to_string(config_file) {
+            if let Ok(json) = serde_json::from_str::<Value>(&config_contents) {
+                if let Some(args_array) = json.get("args").and_then(|v| v.as_array()) {
+                    let config_args = args_array
+                        .iter()
+                        .filter_map(|v| v.as_str().map(String::from))
+                        .collect();
+
+                    return config_args;
+                }
+            }
+        }
+    }
+
+    default_args // Return the default args if config is missing or invalid
 }