Add OpenAI platform: live model fetching with enrichment (provider 1)

The 4th registry row: id "openai", OPENAI_API_KEY env > auth.json
"openai" scope (login picker/paste/validation all registry-generic —
zero TUI changes needed, pinned by the picker test), base
https://api.openai.com/v1 with KIGI_OPENAI_BASE_URL override, Responses
dialect via the new PlatformWireApi spec field, enrichment-backed
metadata (wire_serves_metadata=false).

OpenAI's GET /v1/models returns bare ids and is polluted with
tts/whisper/embeddings entries: the listing is restricted to
enrichment-known TOOL-CALLING models (review caught that membership
alone admitted models.dev-known embeddings models, which would 400 on
every agentic request; dropped ids are debug-logged for launch-day
diagnosability). Context windows, effort menus, display names, and
thinking capability come from the enrichment pipeline — wiremock e2e
pins the full contract: polluted live listing + models.dev →
one Responses-backed chat model with a 400k documented context window.

Responses max-effort wiring (closes the P0c-1 debt): canonical effort
rides a CreateResponseWrapper sidecar and patch_reasoning_effort writes
it onto the serialized body at both send sites (all seven levels pinned,
xhigh/max distinct, summary preserved); normalize_effort_echo drops
echoes async-openai's typed enum cannot represent at both the non-stream
and SSE parse seams; the dead typed to_responses_api converter is
deleted. Kimi/moonshot stay byte-identical (ChatCompletions untouched,
wire_api maps to the same default; kimi wire tests green).

kimi-import now recognizes ANY registry platform host as built-in
(was hardcoded moonshot), covering openai and future rows.

crates/codegen/kigi-shell/src/agent/auth_method.rs

@@ -583,7 +583,8 @@ mod tests {
                 XAI_API_KEY_METHOD_ID,
                 KIMI_CODE_METHOD_ID,
                 MOONSHOT_CN_METHOD_ID,
-                MOONSHOT_AI_METHOD_ID
+                MOONSHOT_AI_METHOD_ID,
+                "openai"
             ]
         );
         assert_eq!(default_id(&built), Some(XAI_API_KEY_METHOD_ID));
@@ -609,7 +610,8 @@ mod tests {
                 CACHED_TOKEN_AUTH_METHOD_ID,
                 KIMI_CODE_METHOD_ID,
                 MOONSHOT_CN_METHOD_ID,
-                MOONSHOT_AI_METHOD_ID
+                MOONSHOT_AI_METHOD_ID,
+                "openai"
             ]
         );
         assert_eq!(default_id(&built), Some(CACHED_TOKEN_AUTH_METHOD_ID));
@@ -628,7 +630,8 @@ mod tests {
                 CACHED_TOKEN_AUTH_METHOD_ID,
                 KIMI_CODE_METHOD_ID,
                 MOONSHOT_CN_METHOD_ID,
-                MOONSHOT_AI_METHOD_ID
+                MOONSHOT_AI_METHOD_ID,
+                "openai"
             ]
         );
         assert_eq!(default_id(&built), Some(CACHED_TOKEN_AUTH_METHOD_ID));
@@ -650,7 +653,8 @@ mod tests {
             vec![
                 KIMI_CODE_METHOD_ID,
                 MOONSHOT_CN_METHOD_ID,
-                MOONSHOT_AI_METHOD_ID
+                MOONSHOT_AI_METHOD_ID,
+                "openai"
             ]
         );
         assert_eq!(default_id(&built), None);