fix(backend): scope Pi model listing to enabled models

backend/src/pi/list-models.ts

@@ -2,7 +2,10 @@ import { spawn as nodeSpawn, type ChildProcessWithoutNullStreams } from "node:ch
 import type { AppConfig } from "../config.js";
 import { RpcClient } from "../rpc/rpc-client.js";
 import { buildPiChildEnv } from "./provider-credentials.js";
-import { secretValue } from "../config/secret-bundle.js";
+import {
+  loadPiEnabledModels,
+  type PiEnabledModelsResult,
+} from "./enabled-models.js";
 
 export interface PiModel {
   provider: string;
@@ -19,6 +22,8 @@ interface Opts {
   ) => ChildProcessWithoutNullStreams;
   ttlMs?: number;
   nowMs?: () => number;
+  loadEnabledModels?: () => PiEnabledModelsResult;
+  warn?: (message: string) => void;
 }
 
 /**
@@ -36,11 +41,15 @@ export function createPiModelLister(cfg: AppConfig, opts: Opts = {}): () => Prom
   return async function listModels(): Promise<PiModel[]> {
     if (cache && now() - cache.at < ttlMs) return cache.models;
 
-    const env = buildPiChildEnv({
-      provider: cfg.defaults.provider,
-      credentialValue: secretValue(cfg, "THT_MODEL_API_KEY"),
-      credentialFile: cfg.modelApiKeyFile,
-    });
+    const enabled = (opts.loadEnabledModels
+      ?? (() => loadPiEnabledModels({ harnessDir: cfg.harnessDir })))();
+    for (const warning of enabled.warnings) opts.warn?.(warning);
+    if (enabled.ids.length === 0) {
+      cache = { at: now(), models: [] };
+      return [];
+    }
+
+    const env = buildPiChildEnv({});
     delete env.THT_DATA_ROOT;
     if (cfg.dataRoot !== undefined) env.THT_DATA_ROOT = cfg.dataRoot;
     const child = spawnFn(cfg.piBin, ["--mode", "rpc"], { cwd: cfg.harnessDir, env });
@@ -52,12 +61,20 @@ export function createPiModelLister(cfg: AppConfig, opts: Opts = {}): () => Prom
         new Promise<never>((_, rej) => setTimeout(() => rej(new Error("pi model list timeout")), 8000)),
       ]);
       const raw = (resp?.data?.models ?? []) as Array<Record<string, unknown>>;
-      const models: PiModel[] = raw.map((m) => ({
+      const available: PiModel[] = raw.map((m) => ({
         provider: String(m.provider ?? ""),
         id: String(m.id ?? ""),
         name: String(m.name ?? m.id ?? ""),
         reasoning: Boolean(m.reasoning),
       }));
+      const byCompositeId = new Map(
+        available.map((model) => [`${model.provider}/${model.id}`, model]),
+      );
+      const models = enabled.ids.flatMap((id) => {
+        const model = byCompositeId.get(id);
+        return model ? [model] : [];
+      });
+      if (models.length === 0) opts.warn?.("No Pi-enabled models are currently available");
       cache = { at: now(), models };
       return models;
     } finally {