feat(core): port Factory::createConfig() as factory::create_config()

Adds crates/mozart-core/src/factory.rs with get_cache_dir(),
get_data_dir(), and create_config() — a Rust port of
Composer\Factory::createConfig() (auth loading and htaccess creation
are out of scope for now).

Also fixes a correctness bug on Linux: the previous Config::default()
resolved cache-dir to $XDG_CONFIG_HOME/composer/cache via the
{$home}/cache placeholder, whereas Composer uses the XDG cache base
($XDG_CACHE_HOME or ~/.cache), giving ~/.cache/composer.

Callers updated:
- Composer::load() uses create_config() as the global baseline before
  merging project-level config.
- config command execute_read() builds the global baseline with
  create_config() and overlays local config on top when not --global,
  matching Composer's actual layering order.

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

1 files changed, 1 insertions, 0 deletions

diff --git a/crates/mozart-core/src/lib.rs b/crates/mozart-core/src/lib.rs
index 1264292..74f3512 100644
--- a/crates/mozart-core/src/lib.rs
+++ b/crates/mozart-core/src/lib.rs
@@ -2,6 +2,7 @@ pub mod composer;
 pub mod config;
 pub mod console;
 pub mod exit_code;
+pub mod factory;
 pub mod http;
 pub mod package;
 pub mod platform;