P6 during the run: split the runner task (02 core, 03 workers); guard.PreCheck as an owner commit; AGENTS.md: write code into files early

Task 02 (the whole runner) ended at 21:08 with no file and no commit: Ornith wrote the
implementation out in its reply (~700 lines), OpenCode compacted the session, and the model
then emitted a malformed tool call. It had also looked for the given test at a wrong path
("_files/…" relative to the plan: my ambiguity).

- 02-runner → 02-runner-core (types, Submit, Status, Touch, Cancel; no goroutines) and
  03-runner-workers; the given test split to match (runner_core_test.go gains three tests:
  queued storage, cancel while queued, Status never moves the lease); later tasks renumbered
  04-09 and every cross-reference checked.
- Copy paths spelled from the repo root.
- guard.PreCheck (+ its test) is committed here by the owner: the old task 05 told the
  implementer to edit internal/guard/, which AGENTS.md forbids. My contradiction.
- AGENTS.md rule 6: write code into files early, in small steps.
Both runner test files compile against a panic-only skeleton (the core file also alone) and
fail there on panic: todo.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/plans/p6/_files/batch/runner_test.go

@@ -4,8 +4,6 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"io"
-	"log/slog"
 	"strings"
 	"sync"
 	"testing"
@@ -15,46 +13,6 @@ import (
 	"git.wntrmute.dev/kyle/sift/internal/dcache"
 )
 
-var (
-	alice = &auth.Caller{Name: "alice", Workspace: "hermes-fleet"}
-	bob   = &auth.Caller{Name: "bob", Workspace: "hermes-fleet"}
-	carol = &auth.Caller{Name: "carol", Workspace: "hermes-fleet"}
-)
-
-func newRunner(t *testing.T, fetch FetchFunc, cfg Config) *Runner {
-	t.Helper()
-	db, err := dcache.Open("", 1<<20, slog.New(slog.NewTextHandler(io.Discard, nil)))
-	if err != nil {
-		t.Fatal(err)
-	}
-	t.Cleanup(func() { _ = db.Close() })
-	r := New(db, fetch, cfg, slog.New(slog.NewTextHandler(io.Discard, nil)))
-	t.Cleanup(r.Close) // runs before db.Close (cleanups are LIFO)
-	return r
-}
-
-func waitStatus(t *testing.T, r *Runner, id, want string) {
-	t.Helper()
-	deadline := time.Now().Add(5 * time.Second)
-	for time.Now().Before(deadline) {
-		j, _, ok := r.Status(id)
-		if ok && j.Status == want {
-			return
-		}
-		time.Sleep(2 * time.Millisecond)
-	}
-	j, _, _ := r.Status(id)
-	t.Fatalf("job %s never reached %q (now %q)", id, want, j.Status)
-}
-
-func urls(ss ...string) []Target {
-	var out []Target
-	for _, s := range ss {
-		out = append(out, Target{URL: "https://" + s + ".example/"})
-	}
-	return out
-}
-
 // Targets run one at a time, in order, and each fetch is given the submitting caller.
 func TestSerialOrderAndCaller(t *testing.T) {
 	var mu sync.Mutex
@@ -235,36 +193,6 @@ func TestResubmitAfterCancelIsNew(t *testing.T) {
 	}
 }
 
-func TestCaps(t *testing.T) {
-	release := make(chan struct{})
-	fetch := func(context.Context, *auth.Caller, Target) (Result, error) {
-		<-release
-		return Result{Content: "ok"}, nil
-	}
-	r := newRunner(t, fetch, Config{TargetsPerJob: 2, JobsTotal: 2})
-	defer close(release)
-	if _, _, err := r.Submit(context.Background(), alice, dcache.ClassFleet, urls("a", "b", "c")); !errors.Is(err, ErrTooManyTargets) {
-		t.Fatalf("3 targets over a cap of 2: want ErrTooManyTargets, got %v", err)
-	}
-	if _, _, err := r.Submit(context.Background(), alice, dcache.ClassFleet, nil); !errors.Is(err, ErrNoTargets) {
-		t.Fatalf("no targets: want ErrNoTargets, got %v", err)
-	}
-	if _, _, err := r.Submit(context.Background(), alice, dcache.ClassFleet, urls("a")); err != nil {
-		t.Fatal(err)
-	}
-	// alice's job is live (queued or running): a second, different list is refused.
-	if _, _, err := r.Submit(context.Background(), alice, dcache.ClassFleet, urls("z")); !errors.Is(err, ErrCallerBusy) {
-		t.Fatalf("want ErrCallerBusy, got %v", err)
-	}
-	if _, _, err := r.Submit(context.Background(), bob, dcache.ClassFleet, urls("b")); err != nil {
-		t.Fatal(err)
-	}
-	// Two live jobs in total: a third caller is refused.
-	if _, _, err := r.Submit(context.Background(), carol, dcache.ClassFleet, urls("c")); !errors.Is(err, ErrBusy) {
-		t.Fatalf("want ErrBusy, got %v", err)
-	}
-}
-
 // Submit returns with the job stored "queued"; it becomes "running" when a worker takes it.
 func TestQueuedThenRunning(t *testing.T) {
 	release := make(chan struct{})
@@ -443,10 +371,3 @@ func TestHooks(t *testing.T) {
 		t.Fatalf("stored result bytes %d, want > 0 for the done target", bytes)
 	}
 }
-
-func TestStatusUnknown(t *testing.T) {
-	r := newRunner(t, func(context.Context, *auth.Caller, Target) (Result, error) { return Result{}, nil }, Config{})
-	if _, _, ok := r.Status("no-such-job"); ok {
-		t.Fatal("unknown id must be ok=false")
-	}
-}