refactor: apply clippy auto-fixes (162 warnings resolved)

- Fix needless borrows and references
- Collapse nested if statements
- Replace manual strip_prefix with str::strip_prefix()
- Remove redundant closures in map/unwrap_or_else
- Use Iterator::next_back() instead of rev().next()
- Simplify map_or patterns
- Use std::io::Error::other() instead of new(ErrorKind::Other, ..)
- Use div_ceil() instead of manual ceiling division
- Consolidate format! string arguments
- Various other idiomatic Rust improvements

39 files changed, 220 insertions(+), 320 deletions(-)

src/application/services/auth_application_service.rs

@@ -152,13 +152,13 @@ impl AuthApplicationService {
     /// Returns whether OIDC is configured and enabled
     pub fn oidc_enabled(&self) -> bool {
         let state = self.oidc.read().unwrap();
-        state.service.is_some() && state.config.as_ref().map_or(false, |c| c.enabled)
+        state.service.is_some() && state.config.as_ref().is_some_and(|c| c.enabled)
     }
 
     /// Returns whether password login is disabled (OIDC-only mode)
     pub fn password_login_disabled(&self) -> bool {
         let state = self.oidc.read().unwrap();
-        state.config.as_ref().map_or(false, |c| c.disable_password_login)
+        state.config.as_ref().is_some_and(|c| c.disable_password_login)
     }
 
     /// Returns a clone of the OIDC config if available