feat(providers): add Xiaomi MiMo (global + China token plan)

Providers 19-20 (22nd & 23rd registry variants), sourced from Pi
(earendil-works/pi). Pi's xiaomi.ts / xiaomi-token-plan-cn.ts use plain
openAICompletionsApi (no thinking dialect) → Kigi Passthrough. Global: MiMo
at api.xiaomimimo.com/v1, XIAOMI_API_KEY, models.dev xiaomi. China token plan:
token-plan-cn.xiaomimimo.com/v1, XIAOMI_TOKEN_PLAN_CN_API_KEY, models.dev
xiaomi-token-plan-cn. Both Bearer + OpenAI listing + ChatCompletions +
restrict_to_enriched; /models auth-gated → validator.

id-match proven vs Pi's static ids (mimo-v2.5-pro, mimo-v2-flash, ...). The
CN token plan lists 4 mimo TTS models (tool_call=false); restrict's tool_call
cut drops them, keeping only the 3 chat models — the e2e proves this
non-vacuously with the real mimo-v2-tts. Review found no defects.

Registry at 23; picker 24 rows (welcome picker verified rendering all rows at
a taller viewport).

crates/codegen/kigi-tui/src/app/app_view.rs

@@ -6894,7 +6894,7 @@ pub(crate) mod tests {
     #[test]
     fn pending_menu_items_lists_interactive_methods_plus_quit() {
         let items = pending_menu_items(&fresh_user_auth_methods(), None);
-        assert_eq!(items.len(), 22, "21 login rows + Quit, got {items:?}");
+        assert_eq!(items.len(), 24, "23 login rows + Quit, got {items:?}");
         assert!(
             matches!(&items[0], PendingMenuItem::Login { label } if label == "Kimi Code (OAuth)"),
             "row 0 must be the OAuth login, got {:?}",
@@ -7041,7 +7041,21 @@ pub(crate) mod tests {
                 label: "Z.AI Coding China (API key)".into(),
             }
         );
-        assert_eq!(items[21], PendingMenuItem::Quit);
+        assert_eq!(
+            items[21],
+            PendingMenuItem::ApiKey {
+                target: PlatformLogin(kigi_shell::models::PlatformId::Xiaomi),
+                label: "Xiaomi MiMo (API key)".into(),
+            }
+        );
+        assert_eq!(
+            items[22],
+            PendingMenuItem::ApiKey {
+                target: PlatformLogin(kigi_shell::models::PlatformId::XiaomiTokenPlanCn),
+                label: "Xiaomi Token Plan China (API key)".into(),
+            }
+        );
+        assert_eq!(items[23], PendingMenuItem::Quit);
         // The non-interactive methods must never appear as rows.
         let byok = kigi_shell::agent::auth_method::build_auth_methods(
             kigi_shell::agent::auth_method::AuthMethodsBuildInputs {
@@ -7052,7 +7066,7 @@ pub(crate) mod tests {
         );
         assert_eq!(
             pending_menu_items(&byok.methods, None).len(),
-            22,
+            24,
             "xai.api_key / cached_token must not add rows"
         );
     }