feat(console): add structured error handling, verbosity, and suggestions

Implement Phase 7.2 error handling & UX infrastructure:

- Add exit_code module with MozartError, bail()/bail_silent() helpers,
  and Composer-compatible exit code constants (0-5, 100)
- Redesign Console struct with Verbosity enum (Quiet/Normal/Verbose/
  VeryVerbose/Debug), ANSI auto-detection via IsTerminal, and
  verbosity-gated output methods (info/verbose/debug/error)
- Thread Console through all 33 command execute() signatures
- Replace all std::process::exit() calls with structured MozartError
  returns handled in main()
- Migrate eprintln\! status messages to console.info() for quiet-mode
  suppression
- Add suggest module with Levenshtein distance and "Did you mean?"
  formatting for future package name suggestions

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

1 files changed, 6 insertions, 4 deletions

diff --git a/crates/mozart/src/commands/global.rs b/crates/mozart/src/commands/global.rs
index 42f3703..e6e7bc8 100644
--- a/crates/mozart/src/commands/global.rs
+++ b/crates/mozart/src/commands/global.rs
@@ -13,7 +13,11 @@ pub struct GlobalArgs {
 
 // ─── Main entry point ────────────────────────────────────────────────────────
 
-pub fn execute(args: &GlobalArgs, cli: &super::Cli) -> anyhow::Result<()> {
+pub fn execute(
+    args: &GlobalArgs,
+    cli: &super::Cli,
+    console: &crate::console::Console,
+) -> anyhow::Result<()> {
     use clap::Parser as _;
     use std::fs;
 
@@ -21,9 +25,7 @@ pub fn execute(args: &GlobalArgs, cli: &super::Cli) -> anyhow::Result<()> {
 
     fs::create_dir_all(&home)?;
 
-    if !cli.quiet {
-        eprintln!("Changed current directory to {}", home.display());
-    }
+    console.info(&format!("Changed current directory to {}", home.display()));
 
     // SAFETY: single-threaded at this point; no concurrent env access
     unsafe {