feat(providers): add Kimi For Coding via static KIMI_API_KEY

Provider 16 (19th registry variant). Same endpoint + models + Kimi dialect
as the existing OAuth kimi-code platform (api.kimi.com/coding/v1 via the
KIGI_CODE_BASE_URL override), but authenticated with a static KIMI_API_KEY
instead of the device flow — for users who have a Kimi For Coding key rather
than an OAuth subscription. Bearer, OpenAI listing, ChatCompletions,
ChatCompat::Kimi, wire_serves_metadata=true (Kimi /models self-serves
context/thinking), restrict_to_enriched=false (clean 3-model catalog).
/coding/v1/models is auth-gated (401) so it doubles as the validator.

No collision: KIMI_API_KEY was previously unused (grep-verified), and the
house BYOK reads only KIGI_API_KEY/XAI_API_KEY/legacy. kimi-code (OAuth) and
kimi-coding (static key) are independently gated (OAuth-token vs key) and
their models get distinct managed keys (kimi-code/k3 vs kimi-coding/k3) — a
user with both simply sees each Kimi model twice; no dedup collision, no crash.

Review (6 areas): no blocking defects; confirmed the spec correctly mirrors
KIMI_CODE_SPEC (differing only in uses_oauth/api_key_envs/console_host/labels)
and the coexistence is benign. Strengthened the e2e's dialect assertion (Kimi
is the default ChatCompat, so it did not discriminate a parse failure) by
also asserting parse_managed_model_key attributes the key to KimiCoding.

Tests: e2e proves wire-served context (1_048_576 from the wire) with the
models.dev fetch SKIPPED (all-wire-metadata provider, .expect(0)), bare-id
round-trip under kimi-coding/, Kimi dialect; validation test rejects a 401
from /models. Registry at 19; picker 20 rows; snapshot already bundles
kimi-for-coding.

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(), 19, "18 login rows + Quit, got {items:?}");
+        assert_eq!(items.len(), 20, "19 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 {:?}",
@@ -7020,7 +7020,14 @@ pub(crate) mod tests {
                 label: "Qwen Token Plan China (API key)".into(),
             }
         );
-        assert_eq!(items[18], PendingMenuItem::Quit);
+        assert_eq!(
+            items[18],
+            PendingMenuItem::ApiKey {
+                target: PlatformLogin(kigi_shell::models::PlatformId::KimiCoding),
+                label: "Kimi For Coding (API key)".into(),
+            }
+        );
+        assert_eq!(items[19], 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 {
@@ -7031,7 +7038,7 @@ pub(crate) mod tests {
         );
         assert_eq!(
             pending_menu_items(&byok.methods, None).len(),
-            19,
+            20,
             "xai.api_key / cached_token must not add rows"
         );
     }