feat: generate the model catalog from live API data

Add a hidden --generate-models flag that rebuilds models.yaml from
models.dev and OpenRouter merged with the hand-owned quirks overlay,
regenerate the committed catalog with it (393 -> 1090 models), and
retire the Python updater. GitHub becomes fully quirks-owned since
upstream only tracks Copilot ids, legacy ids upstream dropped are
preserved as hand-owned quirks entries, and non-chat model families
(image/tts/audio/realtime) are excluded from generation.

src/main.rs

@@ -20,7 +20,7 @@ extern crate log;
 
 use crate::cli::Cli;
 use crate::client::{
-    ModelType, call_chat_completions, call_chat_completions_streaming, list_models, oauth,
+    ModelType, call_chat_completions, call_chat_completions_streaming, catalog, list_models, oauth,
 };
 use crate::config::instructions::WORKSPACE_INSTRUCTIONS_FILE_NAME;
 use crate::config::{
@@ -101,6 +101,7 @@ async fn main() -> Result<()> {
 
     let info_flag = cli.info
         || cli.sync_models
+        || cli.generate_models.is_some()
         || cli.list_models
         || cli.list_roles
         || cli.list_agents
@@ -295,6 +296,10 @@ async fn run(
         return sync_models(&url, abort_signal.clone()).await;
     }
 
+    if let Some(path) = &cli.generate_models {
+        return catalog::generate_models_file(path).await;
+    }
+
     if cli.list_models {
         for model in list_models(ctx.app.config.as_ref(), ModelType::Chat) {
             println!("{}", model.id());