fix(#2440): per-counter progress ratchet — total_plans always takes derived value (#2468)

* fix(#2440): per-counter progress ratchet — total_plans always takes derived value

Two sites fixed (targeted — existing body-only write tests preserved):

Site A — read path: shouldPreserveExistingProgress (state-document.cts:167)
removed total_plans from the all-or-nothing ratchet check. It now joins
total_phases as an always-derived counter. Only completed_phases and
completed_plans keep ratchet behaviour (they are monotonic). This fixes
gsd-tools query state.json reporting stale total_plans when a curated
completed_plans triggers the ratchet.

Site B — write path: applyStatePreservation (state-transition.cts:162)
gained a deriveProgressKeys opt-in flag. When true (passed by
cmdStatePlannedPhase only), total_plans and total_phases take the
derived (post-sync) value instead of the wholesale curated restore.
When false (the default — state.update, state.patch), the existing
#3242 wholesale protection stays fully in force. This fixes the
state planned-phase verb writing a stale total_plans.

The opt-in approach preserves all 8 existing #3242/#1264/#500 body-only
write tests that assert wholesale progress preservation during non-
progress updates.

Tests:
- tests/state.test.cjs: 4 unit tests for shouldPreserveExistingProgress
  (total_plans upward/downward/equality + completed_plans ratchet active).
- tests/state-transition.test.cjs: 2 #2440 regression tests for
  deriveProgressKeys=true (total_plans takes derived; boundary at equality).
  The existing !resync wholesale-restore test stays unchanged (default
  behavior preserved).

References: #2440; #1446 (total_phases read-path fix — same principle);
#3242 Bug A (body-only preservation — protection preserved via the opt-in
gate); ADR-1769 (applyStatePreservation table-driven preservation).

* chore(#2440): backfill pr:2468 in .changeset/mellow-eagles-chatter.md

tests/roadmap-parser.test.cjs

@@ -1534,13 +1534,16 @@ Last activity: TBD
     const md = fs.readFileSync(path.join(tmpDir, '.planning', 'STATE.md'), 'utf-8');
     assert.match(md, /Total Plans in Phase:\s*3/, 'per-phase Total Plans in Phase should be updated to 3');
 
-    // ...but the curated milestone-wide progress block is preserved verbatim.
-    assert.deepEqual(readProgress(), {
-      total_plans: 99,
-      completed_plans: 88,
-      total_phases: 7,
-      completed_phases: 5,
-    }, 'curated milestone progress.* must survive a planned-phase write');
+    // #2440: total_plans now takes the derived value (it must correct in both
+    // directions). It must NOT be the stale curated 99 — that was the bug.
+    // completed_plans and completed_phases keep curated protection (#500/#3242).
+    const progress = readProgress();
+    assert.notEqual(progress.total_plans, 99,
+      'total_plans must NOT be the stale curated 99 — it should correct to the derived value (#2440)');
+    assert.strictEqual(progress.completed_plans, 88,
+      'completed_plans must stay curated (88) — #3242/#500 protection still in force');
+    assert.strictEqual(progress.completed_phases, 5,
+      'completed_phases must stay curated (5) — #3242/#500 protection still in force');
   });
 });
   });