fix(pm): declare the stale-finding sweep's empty path population

Wiring `check:pm-stale-finding` into package.json makes this tool a DECLARING
family for `dispatch-gates`, and `check:declared-population-live` reds on it:
the module-level run fixture's repo slug is the only path-shaped literal in the
file, so the derivation read it as a declared population of one path that names
no tracked file — the same output a gate with no literals produces.

Both halves of the gate's own remedy: the `no-path-population` marker, which is
true of this tool (its whole input is the GitHub API), and the fixture moved
into the self-test body, where the module-body mask reaches it. Top-level VALUE
declarations are deliberately never masked — being unreferenced at module scope
is what a declared population IS — so the comment on the moved fixture says
⛔ do not hoist it.

`check:declared-population-live`: 250 declaring families with 1 unreachable →
249, all reaching. The sweep's 91-case self-test is unchanged.

Claude-Session: https://claude.ai/code/session_01DAcomhvR9kKizeYgg89Vo8
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

scripts/pm/sweep-stale-finding.mjs

@@ -172,6 +172,8 @@ import {
   staleFindingScreen,
 } from './check-half-states.mjs';
 
+// dispatch-gates: no-path-population -- this tool reads no file in the tree at all; its whole input is the GitHub API (one label-scoped issue listing per board, plus the per-card label read-back each write verifies itself against), so no card's file surface can predict it and the honest derivation is a repo-wide undetermined one (#16904)
+
 const SELF_PATH = fileURLToPath(import.meta.url);
 const API = 'https://api.github.com';
 const TOKEN = process.env.GITHUB_TOKEN ?? process.env.GH_TOKEN ?? '';
@@ -947,21 +949,30 @@ function fakeBoard({ cards, failOn = null, afterWrite = null }) {
   return { rest, calls, state };
 }
 
-const OPTIONS = (over = {}) => ({
-  repo: 'o/r',
-  repoSource: '--repo',
-  write: false,
-  json: false,
-  cursor: null,
-  maxCards: DEFAULT_MAX_CARDS,
-  batchSize: DEFAULT_BATCH_SIZE,
-  batchPauseMs: 0,
-  listCap: 25,
-  provenance: '',
-  ...over,
-});
-
 export async function selfTest() {
+  // The run fixture's option bag. Declared HERE rather than at module level,
+  // and that placement is load-bearing: `dispatch-gates`'s module-body mask
+  // blanks self-test BODIES but deliberately never masks top-level VALUE
+  // declarations — an unreferenced top-level const carrying path literals is
+  // how a gate DECLARES its population for that scanner. So a fixture repo slug
+  // spelled at module scope reads as this tool declaring a one-path population
+  // that names no tracked file, which `check:declared-population-live` reds on
+  // (measured, the moment `check:pm-stale-finding` made this a declaring
+  // family). Inside the body it is a fixture again. ⛔ Do not hoist it.
+  const OPTIONS = (over = {}) => ({
+    repo: 'o/r',
+    repoSource: '--repo',
+    write: false,
+    json: false,
+    cursor: null,
+    maxCards: DEFAULT_MAX_CARDS,
+    batchSize: DEFAULT_BATCH_SIZE,
+    batchPauseMs: 0,
+    listCap: 25,
+    provenance: '',
+    ...over,
+  });
+
   const batterySeen = new Map();
   let openBattery = null;
   const battery = (name) => { openBattery = name; };