fix(openai): add built-in GPT-6.1 Sol pricing

Co-authored-by: Codex <noreply@openai.com>

backend/crates/providers/openai/src/transport/usage.rs

@@ -228,7 +228,7 @@ struct PricingRule {
 
 // 价格来源：https://developers.openai.com/api/docs/pricing。
 // 只登记已核验的常规价格及服务档位；临时优惠不写入内置价目。
-// 原有规则于 2026-09-09 核验，新增型号的核验日期见对应条目。
+// 原有规则于 2026-09-09 核验，GPT-6.1 Sol 于 2026-09-29 核验，其余新增型号见对应条目。
 // 已按 https://developers.openai.com/api/docs/deprecations 核验至 2026-09-13，
 // 移除已关闭的型号；仅宣布弃用但尚未到关闭日期的型号继续保留。
 const PRICING_RULES: &[PricingRule] = &[
@@ -244,6 +244,16 @@ const PRICING_RULES: &[PricingRule] = &[
             .with_long_flex(100_000, 375_000, 10_000)
             .with_long_fast(400_000, 1_500_000, 40_000),
     },
+    PricingRule {
+        model: "gpt-6.1-sol",
+        pricing: ModelPricing::new(20_000, 100_000, 1_000)
+            .with_cache_write(125)
+            .with_flex(10_000, 50_000, 500)
+            .with_fast(40_000, 200_000, 2_000)
+            .with_long(40_000, 150_000, 2_000)
+            .with_long_flex(20_000, 75_000, 1_000)
+            .with_long_fast(80_000, 300_000, 4_000),
+    },
     // https://developers.openai.com/api/docs/models/gpt-6-sol，核验日期 2026-09-24。
     PricingRule {
         model: "gpt-6-sol",
@@ -864,7 +874,10 @@ fn reasoning_model(model: &str) -> bool {
     let normalized = normalize_model_name(model);
     let model = pricing_model_name(&normalized);
     model.starts_with("gpt-5")
-        || matches!(model, "gpt-6-astra" | "gpt-6-sol" | "gpt-6-luna")
+        || matches!(
+            model,
+            "gpt-6-astra" | "gpt-6.1-sol" | "gpt-6-sol" | "gpt-6-luna"
+        )
         || model.starts_with("o1")
         || model.starts_with("o3")
         || model.starts_with("o4")

backend/crates/providers/openai/tests/admin.rs

@@ -352,7 +352,14 @@ async fn copying_builtin_prices_keeps_cache_read_and_write_fallback_costs() {
         .await
         .unwrap();
     let prices = bundle.admin_provider().pricing_catalog();
-    for model in ["gpt-4", "gpt-4o", "gpt-6-astra", "gpt-6-sol", "gpt-6-luna"] {
+    for model in [
+        "gpt-4",
+        "gpt-4o",
+        "gpt-6-astra",
+        "gpt-6.1-sol",
+        "gpt-6-sol",
+        "gpt-6-luna",
+    ] {
         let usage = OpenAiBillingUsage::new(100, 10, 20, 15);
         let inherited = openai_billing_breakdown(model, usage, None).unwrap();
         let copied =

backend/crates/providers/openai/tests/transport/canonical.rs

@@ -399,7 +399,7 @@ fn decoder_should_use_non_reasoning_preview_web_search_price() {
 #[test]
 fn gpt_6_decoders_should_use_reasoning_preview_web_search_price() {
     let tools = vec![json!({ "type": "web_search_preview" })];
-    for model in ["gpt-6-astra", "gpt-6-sol", "gpt-6-luna"] {
+    for model in ["gpt-6-astra", "gpt-6.1-sol", "gpt-6-sol", "gpt-6-luna"] {
         let created = json!({
             "type":"response.created",
             "response":{"id":"resp_preview_search_cost","model":model}

backend/crates/providers/openai/tests/transport/usage.rs

@@ -80,6 +80,17 @@ fn astra_billing_should_preserve_components_across_tiers_and_context_boundary()
 fn new_gpt_6_models_should_use_published_prices_across_tiers_and_context_boundary() {
     // 每档依次核对每百万 Token 的输入、缓存读取、缓存写入和输出价格。
     for (model, cases) in [
+        (
+            "gpt-6.1-sol",
+            [
+                (None, 272_000, ["2", "0.1", "2.5", "10"]),
+                (None, 272_001, ["4", "0.2", "5", "15"]),
+                (Some("flex"), 272_000, ["1", "0.05", "1.25", "5"]),
+                (Some("flex"), 272_001, ["2", "0.1", "2.5", "7.5"]),
+                (Some("fast"), 272_000, ["4", "0.2", "5", "20"]),
+                (Some("priority"), 272_001, ["8", "0.4", "10", "30"]),
+            ],
+        ),
         (
             "gpt-6-sol",
             [