feat: make each plugin an npm workspace built by a termix-plugin CLI

plugins/ai/src/backend/providers/registry.ts

@@ -0,0 +1,64 @@
+import { anthropicAdapter } from "./anthropic.js";
+import { geminiAdapter } from "./gemini.js";
+import { ollamaAdapter } from "./ollama.js";
+import { openAiAdapter } from "./openai.js";
+import {
+  AiProviderError,
+  type AiProviderType,
+  type ProviderAdapter,
+} from "./types.js";
+
+/**
+ * openai_compatible reuses the OpenAI adapter: OpenRouter, Groq, Mistral,
+ * DeepSeek, together.ai, LM Studio and vLLM all speak the same wire format,
+ * they differ only in base URL.
+ */
+const ADAPTERS: Record<AiProviderType, ProviderAdapter> = {
+  ollama: ollamaAdapter,
+  anthropic: anthropicAdapter,
+  openai: openAiAdapter,
+  gemini: geminiAdapter,
+  openai_compatible: openAiAdapter,
+};
+
+export function getAdapter(providerType: string): ProviderAdapter {
+  const adapter = ADAPTERS[providerType as AiProviderType];
+  if (!adapter) {
+    throw new AiProviderError(`Unknown provider type: ${providerType}`);
+  }
+  return adapter;
+}
+
+/** Provider types that cannot work without a base URL. */
+export const REQUIRES_BASE_URL: AiProviderType[] = [
+  "ollama",
+  "openai_compatible",
+];
+
+/** Provider types that cannot work without an API key. */
+export const REQUIRES_API_KEY: AiProviderType[] = [
+  "anthropic",
+  "openai",
+  "gemini",
+];
+
+/**
+ * Shown when a provider's model list cannot be fetched: no key entered yet,
+ * the endpoint is unreachable, or the vendor has no list endpoint. Users can
+ * always type a model id the list does not contain, so this is a starting
+ * point rather than a restriction.
+ */
+export const FALLBACK_MODELS: Record<AiProviderType, string[]> = {
+  ollama: [
+    "llama3.2",
+    "llama3.1",
+    "qwen2.5-coder",
+    "mistral",
+    "phi4",
+    "gemma2",
+  ],
+  anthropic: ["claude-opus-5", "claude-sonnet-5", "claude-haiku-4-5"],
+  openai: ["gpt-5", "gpt-5-mini", "o4-mini", "gpt-4.1"],
+  gemini: ["gemini-2.5-pro", "gemini-2.5-flash", "gemini-2.0-flash"],
+  openai_compatible: [],
+};