fix(browse): mirror Composer's HomeCommand semantics

Replace the hand-rolled composer.json -> composer.lock -> Packagist
fallback with a BrowseRepos composite that dispatches via a uniform
find_packages(name) over the root package, the local installed
repository, and the Packagist remote -- matching HomeCommand's
initializeRepos() + findPackages() loop.

- Extend InstalledPackageEntry with homepage/support so the local repo
  carries the same fields HomeCommand reads off
  CompletePackageInterface; propagate them through
  locked_to_installed_entry.
- Collapse three extract_url_from_* helpers into a single
  handle_package mirror.
- Relax is_valid_url to a filter_var(FILTER_VALIDATE_URL) analog (drop
  the http/https scheme allowlist).
- Route warnings and "No package specified" notices to stderr; match
  HomeCommand's exact wording.
- Merge the macOS/Linux open_browser branches; add the literal "web"
  window-title argument on Windows.

1 files changed, 2 insertions, 0 deletions

diff --git a/crates/mozart-autoload/src/autoload.rs b/crates/mozart-autoload/src/autoload.rs
index d245fce..21a1de2 100644
--- a/crates/mozart-autoload/src/autoload.rs
+++ b/crates/mozart-autoload/src/autoload.rs
@@ -1069,6 +1069,8 @@ mod tests {
             install_path: Some(format!("../{name}")),
             autoload: None,
             aliases: vec![],
+            homepage: None,
+            support: None,
             extra_fields: BTreeMap::new(),
         }
     }