fix(#3782): segment verification debt by the archived_milestone stamp in progress step 1.6 (#4001)

* test(#3782): step 1.6 must segment verification debt by the archived stamp

* fix(#3782): segment verification debt by the archived_milestone stamp in progress step 1.6

progress.md step 1.6 read the cross-population summary.total_items as
current-milestone debt while claiming the whole query respects milestone
boundaries. The active tree is milestone-filtered; archived trees are
deliberately unfiltered (each result stamped archived_milestone), so a
healthy current milestone presented six shipped milestones' still-open
items as CURRENT debt on every /gsd-progress run (#3782).

Step 1.6 now computes CURRENT_DEBT/ARCHIVED_DEBT via jq selects on the
stamp, tracks archived_debt separately (visible with its own labeled
header — segmented, never hidden), corrects the scoping claim, and
unwraps the CLI's @file: large-payload redirect before jq so counters
cannot silently read 0. A structural guard test pins the segmentation.
parse_gap_files stays deliberately cross-population.

Emitted-Drift-Ack-Growth: progress.md — #3782: +1406 bytes — step 1.6 gains the CURRENT_DEBT/ARCHIVED_DEBT segmentation jq, the @file: unwrap, and the archived-visibility paragraph; parse-gap paragraph reworded to match

* chore(#3782): changeset fragment (pr number backfilled after PR creation)

* chore(#3782): backfill changeset PR number (4001)

---------

Co-authored-by: sim <sim@local>

tests/progress-debt-segmentation-guard.test.cjs

@@ -0,0 +1,65 @@
+'use strict';
+
+// ─────────────────────────────────────────────────────────────────────────────
+// #3782 — progress.md step 1.6 must SEGMENT verification debt by the
+// `archived_milestone` stamp instead of reading the cross-population
+// `summary.total_items`.
+//
+// `query audit-uat` milestone-filters the ACTIVE tree but deliberately adds
+// ARCHIVED trees unfiltered (each result stamped `archived_milestone`), while
+// `summary.total_items` spans both populations. Reading that summary as
+// current-milestone debt made every /gsd-progress run present six shipped
+// milestones' worth of still-open items as CURRENT debt (49 reported vs 13
+// real). The fix counts non-archived results only and gives archived debt its
+// own labeled line — segmented, never hidden (an item archived still-open is
+// still open; the reporter's archived set included an unrun security
+// boundary test).
+// ─────────────────────────────────────────────────────────────────────────────
+
+const { test } = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const path = require('node:path');
+
+const PROGRESS_MD = path.join(__dirname, '..', 'gsd-core', 'workflows', 'progress.md');
+
+// progress.md is shipped workflow text — the bytes ARE what the runtime
+// loads, so a structural scan over it tests the deployed contract (same
+// shape as tests/config-get-raw-guard.test.cjs, which needs no marker for
+// .md reads).
+function step16() {
+  const md = fs.readFileSync(PROGRESS_MD, 'utf-8');
+  const start = md.indexOf('**Step 1.6: Cross-phase health check**');
+  assert.ok(start > 0, 'progress.md must contain Step 1.6');
+  const end = md.indexOf('**Step 1.7:', start);
+  assert.ok(end > start, 'progress.md must contain Step 1.7 after 1.6');
+  return md.slice(start, end);
+}
+
+test('#3782: step 1.6 counts current-milestone debt from non-archived results only', () => {
+  const step = step16();
+  assert.ok(
+    /select\(has\("archived_milestone"\)\s*\|\s*not\)/.test(step),
+    '#3782: the debt count must select results WITHOUT the archived_milestone stamp',
+  );
+  assert.ok(
+    !/Track:\s*`outstanding_debt`\s*—\s*`summary\.total_items`/.test(step),
+    '#3782: outstanding_debt must not read the cross-population summary.total_items',
+  );
+  assert.ok(
+    !/which respects milestone boundaries/.test(step),
+    '#3782: the false whole-query milestone-boundaries claim must be corrected (only the active tree is filtered)',
+  );
+});
+
+test('#3782: archived debt stays visible with its own labeled line', () => {
+  const step = step16();
+  assert.ok(
+    /archived_debt/.test(step),
+    '#3782: archived debt must be tracked as its own value',
+  );
+  assert.ok(
+    /items still open in archived milestones\)/.test(step),
+    '#3782: the warning header must label the archived segment — segmented, not hidden',
+  );
+});