feat: eval run command — prepare, execute, collect pipeline

Implement the uwf-eval run <task-dir> command with 3-phase pipeline:

- prepare: read task.yaml, copy fixture/ to temp workdir
- execute: shell out to uwf thread start + exec
- collect: run judges, compute weighted score, store CAS node,
  set @uwf/eval/<task>/latest variable

Changes:
- src/runner/ — types, prepare, execute, collect, index
- src/storage/store.ts — createEvalStore(), setEvalLatest()
- src/commands/run.ts — full pipeline wiring with --agent/--model/--count
- 9 new tests (prepare + collect + weighted scoring)

Builtin judges return placeholder score 0 (Phase 1c).

Refs #70

packages/eval/src/runner/collect.ts

@@ -0,0 +1,150 @@
+import { execFileSync } from "node:child_process";
+import { readFile } from "node:fs/promises";
+import { resolve } from "node:path";
+
+import type { JSONSchema, Store } from "@ocas/core";
+import { putSchema } from "@ocas/core";
+import type { CasRef } from "@united-workforce/protocol";
+import { createLogger } from "@united-workforce/util";
+
+import type { JudgeOutput } from "../judge/index.js";
+import type { EvalJudgeRecord, EvalRunPayload } from "../storage/index.js";
+import { EVAL_RUN_SCHEMA, setEvalLatest } from "../storage/index.js";
+import type { JudgeEntry } from "../task/index.js";
+import type {
+  CollectInput,
+  CollectResult,
+  JudgeRunner,
+  JudgeRunOutput,
+  JudgeSummary,
+} from "./types.js";
+
+const log = createLogger({ sink: { kind: "stderr" } });
+
+const LOG_JUDGE = "CT6N3P2K";
+const LOG_STORED = "CT9V2Q7M";
+
+/** Permissive schema for judge data without a dedicated schema (e.g. builtin placeholders). */
+const GENERIC_DATA_SCHEMA: JSONSchema = { type: "object" };
+
+/**
+ * Compute the weighted overall score. Judges with weight 0 are informational
+ * and do not affect the result (they contribute 0 to both numerator and
+ * denominator). Returns 0 when total weight is 0.
+ */
+export function computeOverall(judges: ReadonlyArray<{ score: number; weight: number }>): number {
+  let totalWeight = 0;
+  let weighted = 0;
+  for (const judge of judges) {
+    totalWeight += judge.weight;
+    weighted += judge.score * judge.weight;
+  }
+  return totalWeight > 0 ? weighted / totalWeight : 0;
+}
+
+/** Run a task-provided judge script: `node <entry> <cwd> <threadId>`. */
+async function runTaskJudge(
+  taskDir: string,
+  workDir: string,
+  threadId: string,
+  judge: JudgeEntry,
+): Promise<JudgeRunOutput> {
+  if (judge.entry === null) {
+    throw new Error(`judge "${judge.name}" is not builtin but has no entry`);
+  }
+  const entryPath = resolve(taskDir, judge.entry);
+
+  let stdout: string;
+  try {
+    stdout = execFileSync("node", [entryPath, workDir, threadId], {
+      encoding: "utf8",
+      stdio: ["ignore", "pipe", "pipe"],
+      maxBuffer: 50 * 1024 * 1024,
+    });
+  } catch (e) {
+    const message = e instanceof Error ? e.message : String(e);
+    throw new Error(`judge "${judge.name}" failed: ${message}`);
+  }
+
+  const line = stdout.trim().split("\n").pop()?.trim() ?? "";
+  let parsed: unknown;
+  try {
+    parsed = JSON.parse(line);
+  } catch {
+    throw new Error(`judge "${judge.name}" stdout is not valid JSON: ${line || "(empty)"}`);
+  }
+  const output = parsed as JudgeOutput;
+  if (typeof output.score !== "number") {
+    throw new Error(`judge "${judge.name}" output missing numeric score`);
+  }
+
+  const schema =
+    judge.schema !== null ? await loadSchema(resolve(taskDir, judge.schema)) : GENERIC_DATA_SCHEMA;
+  return { score: output.score, data: output.data, schema };
+}
+
+/** Load and parse an OCAS JSON Schema file. */
+async function loadSchema(path: string): Promise<JSONSchema> {
+  const text = await readFile(path, "utf8");
+  return JSON.parse(text) as JSONSchema;
+}
+
+/**
+ * Default judge runner. Builtin judges are skipped for now (placeholder score 0
+ * with empty data); task judges spawn their entry script.
+ */
+const defaultJudgeRunner: JudgeRunner = async (taskDir, workDir, threadId, judge) => {
+  if (judge.builtin) {
+    return { score: 0, data: {}, schema: GENERIC_DATA_SCHEMA };
+  }
+  return runTaskJudge(taskDir, workDir, threadId, judge);
+};
+
+/** Persist judge data to CAS under its schema and return the CAS hash. */
+async function storeJudgeData(store: Store, schema: JSONSchema, data: unknown): Promise<CasRef> {
+  const schemaHash = await putSchema(store, schema);
+  return (await store.cas.put(schemaHash, data)) as CasRef;
+}
+
+/**
+ * Run all judges, store their data and the overall eval-run record in CAS, then
+ * index the run under `@uwf/eval/<task>/latest`.
+ */
+export async function collect(
+  input: CollectInput,
+  runJudge: JudgeRunner = defaultJudgeRunner,
+): Promise<CollectResult> {
+  const { evalStore, taskDir, workDir, threadId, manifest, config } = input;
+  const { store, varStore } = evalStore;
+
+  const records: EvalJudgeRecord[] = [];
+  for (const judge of manifest.judges) {
+    const result = await runJudge(taskDir, workDir, threadId, judge);
+    const dataHash = await storeJudgeData(store, result.schema, result.data);
+    records.push({ name: judge.name, score: result.score, weight: judge.weight, dataHash });
+    log(LOG_JUDGE, `judge=${judge.name} score=${result.score} weight=${judge.weight}`);
+  }
+
+  const overall = computeOverall(records);
+
+  const payload: EvalRunPayload = {
+    task: manifest.name,
+    config,
+    threadId,
+    judges: records,
+    overall,
+    timestamp: Date.now(),
+  };
+
+  const schemaHash = await putSchema(store, EVAL_RUN_SCHEMA);
+  const runHash = (await store.cas.put(schemaHash, payload)) as string;
+  setEvalLatest(varStore, manifest.name, runHash);
+  log(LOG_STORED, `stored eval-run task=${manifest.name} hash=${runHash} overall=${overall}`);
+
+  const judges: JudgeSummary[] = records.map((r) => ({
+    name: r.name,
+    score: r.score,
+    weight: r.weight,
+  }));
+  return { runHash, overall, judges };
+}