Add marketplace command (#17087)

Added a new top-level `codex marketplace add` command for installing
plugin marketplaces into Codex’s local marketplace cache.

This change adds source parsing for local directories, GitHub shorthand,
and git URLs, supports optional `--ref` and git-only `--sparse` checkout
paths, stages the source in a temp directory, validates the marketplace
manifest, and installs it under
`$CODEX_HOME/marketplaces/<marketplace-name>`

Included tests cover local install behavior in the CLI and marketplace
discovery from installed roots in core. Scoped formatting and fix passes
were run, and targeted CLI/core tests passed.

codex-rs/cli/src/main.rs

@@ -38,10 +38,12 @@ use supports_color::Stream;
 mod app_cmd;
 #[cfg(target_os = "macos")]
 mod desktop_app;
+mod marketplace_cmd;
 mod mcp_cmd;
 #[cfg(not(windows))]
 mod wsl_paths;
 
+use crate::marketplace_cmd::MarketplaceCli;
 use crate::mcp_cmd::McpCli;
 
 use codex_core::config::Config;
@@ -105,6 +107,9 @@ enum Subcommand {
     /// Manage external MCP servers for Codex.
     Mcp(McpCli),
 
+    /// Manage plugin marketplaces for Codex.
+    Marketplace(MarketplaceCli),
+
     /// Start Codex as an MCP server (stdio).
     McpServer,
 
@@ -704,6 +709,18 @@ async fn cli_main(arg0_paths: Arg0DispatchPaths) -> anyhow::Result<()> {
             prepend_config_flags(&mut mcp_cli.config_overrides, root_config_overrides.clone());
             mcp_cli.run().await?;
         }
+        Some(Subcommand::Marketplace(mut marketplace_cli)) => {
+            reject_remote_mode_for_subcommand(
+                root_remote.as_deref(),
+                root_remote_auth_token_env.as_deref(),
+                "marketplace",
+            )?;
+            prepend_config_flags(
+                &mut marketplace_cli.config_overrides,
+                root_config_overrides.clone(),
+            );
+            marketplace_cli.run().await?;
+        }
         Some(Subcommand::AppServer(app_server_cli)) => {
             let AppServerCommand {
                 subcommand,