feat(ai): provider factories, per-provider catalogs, createProvider (phase 3)

Auth helpers in src/auth/helpers.ts: envApiKeyAuth() (stored key wins,
then env vars in order, with secret-prompt login) and lazyOAuth()
(flow loads on first use through bundler-opaque dynamic imports in
utils/oauth/load.ts; the OAuthAuth flow exports land in phase 4).
There is no OAuth factory toggle: providers that support OAuth always
attach it, advertising costs nothing until login/refresh runs.

createProvider() in models.ts builds providers from parts: single API
implementation or a map dispatched on model.api (mixed-API providers
like opencode and github-copilot); unknown api yields a stream error.

generate-models.ts now emits one providers/<id>.models.ts catalog per
provider (35 files, biome-excluded like models.generated.ts) and
models.generated.ts becomes a generated aggregator, so importing one
provider factory pulls one catalog. Typed getModel globals unchanged.

One factory per built-in provider under src/providers/: envApiKeyAuth
for standard providers, OAuth for anthropic/openai-codex/github-copilot,
ambient ApiKeyAuth for amazon-bedrock (AWS env/profile/IAM) and
google-vertex (explicit key or ADC+project+location).

providers/all.ts: builtinProviders(), builtinModels(), getBuiltin*
re-exports. fauxProvider() factory returns a real Provider for tests;
legacy registerFauxProvider() unchanged.

packages/ai/src/providers/groq.models.ts

@@ -0,0 +1,127 @@
+// This file is auto-generated by scripts/generate-models.ts
+// Do not edit manually - run 'npm run generate-models' to update
+
+import type { Model } from "../types.ts";
+
+export const GROQ_MODELS = {
+	"llama-3.1-8b-instant": {
+		id: "llama-3.1-8b-instant",
+		name: "Llama 3.1 8B",
+		api: "openai-completions",
+		provider: "groq",
+		baseUrl: "https://api.groq.com/openai/v1",
+		reasoning: false,
+		input: ["text"],
+		cost: {
+			input: 0.05,
+			output: 0.08,
+			cacheRead: 0,
+			cacheWrite: 0,
+		},
+		contextWindow: 131072,
+		maxTokens: 131072,
+	} satisfies Model<"openai-completions">,
+	"llama-3.3-70b-versatile": {
+		id: "llama-3.3-70b-versatile",
+		name: "Llama 3.3 70B",
+		api: "openai-completions",
+		provider: "groq",
+		baseUrl: "https://api.groq.com/openai/v1",
+		reasoning: false,
+		input: ["text"],
+		cost: {
+			input: 0.59,
+			output: 0.79,
+			cacheRead: 0,
+			cacheWrite: 0,
+		},
+		contextWindow: 131072,
+		maxTokens: 32768,
+	} satisfies Model<"openai-completions">,
+	"meta-llama/llama-4-scout-17b-16e-instruct": {
+		id: "meta-llama/llama-4-scout-17b-16e-instruct",
+		name: "Llama 4 Scout 17B 16E",
+		api: "openai-completions",
+		provider: "groq",
+		baseUrl: "https://api.groq.com/openai/v1",
+		reasoning: false,
+		input: ["text", "image"],
+		cost: {
+			input: 0.11,
+			output: 0.34,
+			cacheRead: 0,
+			cacheWrite: 0,
+		},
+		contextWindow: 131072,
+		maxTokens: 8192,
+	} satisfies Model<"openai-completions">,
+	"openai/gpt-oss-120b": {
+		id: "openai/gpt-oss-120b",
+		name: "GPT OSS 120B",
+		api: "openai-completions",
+		provider: "groq",
+		baseUrl: "https://api.groq.com/openai/v1",
+		reasoning: true,
+		input: ["text"],
+		cost: {
+			input: 0.15,
+			output: 0.6,
+			cacheRead: 0.075,
+			cacheWrite: 0,
+		},
+		contextWindow: 131072,
+		maxTokens: 65536,
+	} satisfies Model<"openai-completions">,
+	"openai/gpt-oss-20b": {
+		id: "openai/gpt-oss-20b",
+		name: "GPT OSS 20B",
+		api: "openai-completions",
+		provider: "groq",
+		baseUrl: "https://api.groq.com/openai/v1",
+		reasoning: true,
+		input: ["text"],
+		cost: {
+			input: 0.075,
+			output: 0.3,
+			cacheRead: 0.0375,
+			cacheWrite: 0,
+		},
+		contextWindow: 131072,
+		maxTokens: 65536,
+	} satisfies Model<"openai-completions">,
+	"openai/gpt-oss-safeguard-20b": {
+		id: "openai/gpt-oss-safeguard-20b",
+		name: "Safety GPT OSS 20B",
+		api: "openai-completions",
+		provider: "groq",
+		baseUrl: "https://api.groq.com/openai/v1",
+		reasoning: true,
+		input: ["text"],
+		cost: {
+			input: 0.075,
+			output: 0.3,
+			cacheRead: 0.037,
+			cacheWrite: 0,
+		},
+		contextWindow: 131072,
+		maxTokens: 65536,
+	} satisfies Model<"openai-completions">,
+	"qwen/qwen3-32b": {
+		id: "qwen/qwen3-32b",
+		name: "Qwen3-32B",
+		api: "openai-completions",
+		provider: "groq",
+		baseUrl: "https://api.groq.com/openai/v1",
+		reasoning: true,
+		thinkingLevelMap: {"minimal":null,"low":null,"medium":null,"high":"default"},
+		input: ["text"],
+		cost: {
+			input: 0.29,
+			output: 0.59,
+			cacheRead: 0,
+			cacheWrite: 0,
+		},
+		contextWindow: 131072,
+		maxTokens: 40960,
+	} satisfies Model<"openai-completions">,
+} as const;