feat(#93): IMP-55 u1~u12 frontend manual section swap detection (manual_section_assignment bool axis + drag-only marker gate + dual-axis persistence + backend manual-true gate)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Front/client/tests/user_overrides_restore.test.ts

@@ -54,6 +54,11 @@ function makeSelection(overrides?: Partial<UserSelection["overrides"]>): UserSel
       // axis declared on `UserSelection.overrides`. Empty by default so the
       // existing IMP-52 cases remain unchanged in shape.
       image_overrides: {},
+      // IMP-55 (#93) u3 — bool intent marker is REQUIRED on
+      // `UserSelection.overrides` (not optional). Default to `false` so every
+      // pre-existing fixture matches the `createInitialUserSelection` seed
+      // and stays compile-clean after u3 widened the type.
+      manual_section_assignment: false,
       ...overrides,
     },
   };
@@ -460,3 +465,88 @@ describe("image_overrides axis — saveImageOverride (IMP-51 u11)", () => {
     expect(sel.overrides.image_overrides).toEqual(before);
   });
 });
+
+// ─── IMP-55 (#93) u3 — manual_section_assignment bool axis ──────────────────
+// Restore-on-reopen / seed coverage for the bool intent marker. Production
+// branch lives at `slidePlanUtils.ts` — `applyPersistedNonFrameOverrides`
+// guards with `typeof persisted.manual_section_assignment === "boolean"`,
+// and `createInitialUserSelection` seeds the axis to `false`. The marker
+// gates whether `handleGenerate` (u7) forwards `overrides.zoneSections`
+// to the backend; the pipeline (u9) consumes persisted `zone_sections`
+// only when the marker is exactly `true`, so any non-boolean payload MUST
+// end up `false` in memory (fail-closed).
+
+describe("manual_section_assignment axis — applyPersistedNonFrameOverrides (IMP-55 #93 u3)", () => {
+  it("restores literal true verbatim", () => {
+    const sel = makeSelection();
+    const next = applyPersistedNonFrameOverrides(sel, {
+      manual_section_assignment: true,
+    });
+    expect(next.overrides.manual_section_assignment).toBe(true);
+  });
+
+  it("restores literal false verbatim (u12 apply/cancel write must survive reopen)", () => {
+    // Seed `true` so the assertion proves `false` overwrites; a truthiness
+    // check instead of `typeof === \"boolean\"` would silently keep `true`
+    // and resurrect stale auto-carry assignments as user intent.
+    const sel = makeSelection({ manual_section_assignment: true });
+    const next = applyPersistedNonFrameOverrides(sel, {
+      manual_section_assignment: false,
+    });
+    expect(next.overrides.manual_section_assignment).toBe(false);
+  });
+
+  it("leaves the in-memory marker unchanged when the persisted axis is absent", () => {
+    const sel = makeSelection({ manual_section_assignment: true });
+    const next = applyPersistedNonFrameOverrides(sel, { layout: "horizontal-2" });
+    expect(next.overrides.manual_section_assignment).toBe(true);
+    expect(next.overrides.layout_preset).toBe("horizontal-2");
+  });
+
+  it.each([
+    ["null clear sentinel", null],
+    ['string "true"', "true"],
+    ['string "false"', "false"],
+    ["number 1", 1],
+    ["number 0", 0],
+    ["object {}", {}],
+    ["array []", []],
+  ])("ignores non-boolean payload (%s) — keeps prior in-memory value", (_label, payload) => {
+    const sel = makeSelection({ manual_section_assignment: true });
+    const next = applyPersistedNonFrameOverrides(sel, {
+      manual_section_assignment: payload as unknown as boolean,
+    });
+    expect(next.overrides.manual_section_assignment).toBe(true);
+  });
+
+  it("seeds an empty selection with manual_section_assignment=false (createInitialUserSelection)", () => {
+    const sel = createInitialUserSelection();
+    expect(sel.overrides.manual_section_assignment).toBe(false);
+  });
+
+  it("returns a NEW selection object (no input mutation) when restoring the marker", () => {
+    const sel = makeSelection({ manual_section_assignment: false });
+    const next = applyPersistedNonFrameOverrides(sel, {
+      manual_section_assignment: true,
+    });
+    expect(next).not.toBe(sel);
+    expect(next.overrides).not.toBe(sel.overrides);
+    // Input still pristine — proves the helper does not flip the fixture.
+    expect(sel.overrides.manual_section_assignment).toBe(false);
+  });
+
+  it("layers the bool axis alongside other persisted axes in a single call", () => {
+    const sel = makeSelection();
+    const next = applyPersistedNonFrameOverrides(sel, {
+      layout: "vertical-2",
+      zone_sections: { top: ["03-1"], bottom: ["03-2"] },
+      manual_section_assignment: true,
+    });
+    expect(next.overrides.layout_preset).toBe("vertical-2");
+    expect(next.overrides.zone_sections).toEqual({
+      top: ["03-1"],
+      bottom: ["03-2"],
+    });
+    expect(next.overrides.manual_section_assignment).toBe(true);
+  });
+});