fix(models): complete GPT-5 Chat registration

CHANGELOG.md

@@ -15,7 +15,7 @@ All notable changes to the Tachikoma project will be documented in this file.
 - Removed stale direct model support for retired or non-canonical IDs including GPT-5.1/5.2/pseudo-thinking models, deprecated Claude Sonnet/Opus 4 snapshots, Grok 2/3/4-fast rows, old Groq Llama/Mixtral/Gemma aliases, stale Mistral aliases, and invalid LM Studio `current`.
 
 ### Fixed
-- OpenAI `gpt-5-chat-latest` now preserves its distinct model identity instead of being rewritten to `chat-latest`.
+- OpenAI `gpt-5-chat-latest` now preserves its distinct model identity, appears in model listings, and applies GPT-5 parameter filtering instead of being rewritten to `chat-latest`.
 - SwiftPM consumers now resolve Commander from the package URL instead of accidentally inheriting a sibling local checkout.
 - Ollama model parsing now preserves explicit custom vision model IDs such as `qwen2.5vl:3b` instead of falling back to `llama3.3` (#16).
 - Auth resolution now snapshots environment-ignore state consistently, preventing parallel tests and concurrent callers from falling back to stored OpenRouter credentials when an environment override is present.

Sources/Tachikoma/Core/ModelCapabilities.swift

@@ -242,6 +242,7 @@ public final class ModelCapabilityRegistry: @unchecked Sendable {
         )
 
         self.capabilities["openai:chat-latest"] = gpt5Capabilities
+        self.capabilities["openai:gpt-5-chat-latest"] = gpt5Capabilities
         self.capabilities["openai:gpt-5.5"] = gpt5Capabilities
         self.capabilities["openai:gpt-5.4"] = gpt5Capabilities
         self.capabilities["openai:gpt-5.4-mini"] = gpt5Capabilities

Sources/Tachikoma/Models/Model.swift

@@ -57,6 +57,7 @@ public enum LanguageModel: Sendable, CustomStringConvertible, Hashable {
         public static var allCases: [OpenAI] {
             [
                 .chatLatest,
+                .gpt5ChatLatest,
                 .gpt55,
                 .gpt54,
                 .gpt54Mini,

Tests/TachikomaTests/Core/LanguageModelCoverageTests.swift

@@ -6,6 +6,7 @@ struct LanguageModelCoverageTests {
     func `OpenAI enum exposes properties`() {
         let models = LanguageModel.OpenAI.allCases
         #expect(!models.isEmpty)
+        #expect(models.contains(.gpt5ChatLatest))
         for model in models {
             #expect(!model.modelId.isEmpty)
             _ = model.supportsVision

Tests/TachikomaTests/Core/ModelCapabilitiesTests.swift

@@ -7,6 +7,7 @@ enum ModelCapabilitiesTests {
         @Test
         func `GPT-5 models exclude temperature and topP`() {
             let models: [LanguageModel] = [
+                .openai(.gpt5ChatLatest),
                 .openai(.gpt55),
                 .openai(.gpt54),
                 .openai(.gpt54Mini),