feat(auth): default register to GitHub, add --email flag

hotdata auth register now defaults to GitHub OAuth signup; pass
--email to use email/password instead. The method query param is
forwarded to the webapp cli_register endpoint.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: eddietejeda

src/auth.rs

@@ -371,7 +371,7 @@ pub fn login() {
     }
 }
 
-pub fn register() {
+pub fn register(use_email: bool) {
     let profile_config = config::load("default").unwrap_or_default();
     let app_url = profile_config.app_url.to_string();
 
@@ -391,12 +391,14 @@ pub fn register() {
         tiny_http::Server::http("127.0.0.1:0").expect("failed to start local callback server");
     let port = server.server_addr().to_ip().unwrap().port();
 
+    let method = if use_email { "email" } else { "github" };
     let register_url = format!(
         "{app_url}/auth/cli-register/\
         ?code_challenge={code_challenge}\
         &code_challenge_method=S256\
         &state={state}\
-        &callback_port={port}",
+        &callback_port={port}\
+        &method={method}",
         app_url = app_url.trim_end_matches('/'),
     );
 

src/command.rs

@@ -274,8 +274,12 @@ pub enum AuthCommands {
     /// Log in via browser (same as `hotdata auth` with no subcommand)
     Login,
 
-    /// Create a new account via browser
-    Register,
+    /// Create a new account via browser (defaults to GitHub OAuth)
+    Register {
+        /// Sign up with email and password instead of GitHub
+        #[arg(long)]
+        email: bool,
+    },
 
     /// Remove authentication for a profile
     Logout,

src/main.rs

@@ -158,7 +158,7 @@ fn main() {
         Some(cmd) => match cmd {
             Commands::Auth { command } => match command {
                 None | Some(AuthCommands::Login) => auth::login(),
-                Some(AuthCommands::Register) => auth::register(),
+                Some(AuthCommands::Register { email }) => auth::register(email),
                 Some(AuthCommands::Status) => auth::status("default"),
                 Some(AuthCommands::Logout) => auth::logout("default"),
             },