feat(#90): IMP-56 u1-u19 catch-up before final close (post-u20 push fix)

u1: text_overrides axis in user_overrides_io
u2: structure_overrides axis in user_overrides_io
u3: vite allowlist for new endpoints
u4: text_override_resolver
u5: Step 12 text_overrides apply in phase_z2_pipeline
u6: structure_override_resolver
u7: text_path_stamper
u8: SlideCanvas text-edit capture
u9: SlideCanvas structure-edit overlay
u10: userOverridesApi service extension
u11: designAgent types extension
u12: slidePlanUtils restore
u13: user_overrides endpoint tests
u14: user_overrides restore tests
u15: pipeline fallback tests
u16: edit-mode state + gating tests
u17: slide_base print mode CSS
u18: /api/connect endpoint (vite)
u19: /api/export endpoint (vite)

Recovery scope: 29 files (12 modified + 17 new). u20 already pushed in
9439575; this commit lands u1-u19 that were authored but not committed
before #90 was externally closed.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Front/client/tests/user_overrides_restore.test.ts

@@ -35,6 +35,8 @@ import {
   deriveUserOverridesKey,
   remapPersistedFramesToZoneFrames,
   saveImageOverride,
+  saveTextOverride,
+  saveStructureOverride,
 } from "../src/utils/slidePlanUtils";
 
 // ─── Fixtures ───────────────────────────────────────────────────────────────
@@ -59,6 +61,11 @@ function makeSelection(overrides?: Partial<UserSelection["overrides"]>): UserSel
       // pre-existing fixture matches the `createInitialUserSelection` seed
       // and stays compile-clean after u3 widened the type.
       manual_section_assignment: false,
+      // IMP-56 (#90) u15 — keep the fixture in sync with the two Step-22
+      // persist axes declared on `UserSelection.overrides`. Empty by
+      // default so pre-existing cases retain their shape.
+      text_overrides: {},
+      structure_overrides: {},
       ...overrides,
     },
   };
@@ -550,3 +557,150 @@ describe("manual_section_assignment axis — applyPersistedNonFrameOverrides (IM
     expect(next.overrides.manual_section_assignment).toBe(true);
   });
 });
+
+// ─── IMP-56 (#90) u15 — text_overrides + structure_overrides axes ───────────
+// Pure helpers wired by Home.tsx into the SlideCanvas u13 focusout capture
+// (text) and u14 structure overlay emit (structure). Tests cover:
+//   • saveTextOverride / saveStructureOverride immutability + merge semantics
+//   • createInitialUserSelection seeding the two new axes empty
+//   • applyPersistedNonFrameOverrides layering via the u10 extract helpers
+
+describe("text_overrides axis — saveTextOverride (IMP-56 u15)", () => {
+  it("records a fresh (zoneId, textPath, value) tuple", () => {
+    const sel = makeSelection();
+    const next = saveTextOverride(sel, "top", "row_1_left_body.0", "분석 결과");
+    expect(next.overrides.text_overrides).toEqual({
+      top: { "row_1_left_body.0": "분석 결과" },
+    });
+  });
+
+  it("merges within the same zone without erasing prior text_paths", () => {
+    const sel = makeSelection({
+      text_overrides: { top: { "row_1_left_body.0": "기존" } },
+    });
+    const next = saveTextOverride(sel, "top", "row_1_left_body.1", "신규");
+    expect(next.overrides.text_overrides.top).toEqual({
+      "row_1_left_body.0": "기존",
+      "row_1_left_body.1": "신규",
+    });
+  });
+
+  it("overwrites the same textPath value within a zone", () => {
+    const sel = makeSelection({
+      text_overrides: { top: { "headline.0": "v1" } },
+    });
+    const next = saveTextOverride(sel, "top", "headline.0", "v2");
+    expect(next.overrides.text_overrides.top).toEqual({ "headline.0": "v2" });
+  });
+
+  it("does not mutate the input selection (immutable contract)", () => {
+    const sel = makeSelection({
+      text_overrides: { top: { "headline.0": "before" } },
+    });
+    saveTextOverride(sel, "top", "headline.0", "after");
+    expect(sel.overrides.text_overrides).toEqual({
+      top: { "headline.0": "before" },
+    });
+  });
+
+  it("seeds an empty text_overrides on a fresh selection", () => {
+    const sel = createInitialUserSelection();
+    expect(sel.overrides.text_overrides).toEqual({});
+  });
+});
+
+describe("structure_overrides axis — saveStructureOverride (IMP-56 u15)", () => {
+  it("records a fresh (zoneId → {slot_order, hidden_slots}) tuple", () => {
+    const sel = makeSelection();
+    const next = saveStructureOverride(sel, "top", {
+      slot_order: ["b", "a"],
+      hidden_slots: ["c"],
+    });
+    expect(next.overrides.structure_overrides).toEqual({
+      top: { slot_order: ["b", "a"], hidden_slots: ["c"] },
+    });
+  });
+
+  it("replaces an existing zone entry verbatim (no merge within zone)", () => {
+    const sel = makeSelection({
+      structure_overrides: { top: { slot_order: ["a", "b"], hidden_slots: [] } },
+    });
+    const next = saveStructureOverride(sel, "top", {
+      slot_order: ["b", "a"],
+      hidden_slots: ["a"],
+    });
+    expect(next.overrides.structure_overrides.top).toEqual({
+      slot_order: ["b", "a"],
+      hidden_slots: ["a"],
+    });
+  });
+
+  it("keeps unrelated zones intact when updating one zone", () => {
+    const sel = makeSelection({
+      structure_overrides: {
+        top: { slot_order: ["x"], hidden_slots: [] },
+        bottom_l: { slot_order: ["y"], hidden_slots: ["z"] },
+      },
+    });
+    const next = saveStructureOverride(sel, "top", {
+      slot_order: ["x", "x2"],
+      hidden_slots: [],
+    });
+    expect(next.overrides.structure_overrides.bottom_l).toEqual({
+      slot_order: ["y"],
+      hidden_slots: ["z"],
+    });
+  });
+
+  it("does not mutate the input perZone object after save", () => {
+    const sel = makeSelection();
+    const perZone = { slot_order: ["a"], hidden_slots: ["b"] };
+    const next = saveStructureOverride(sel, "top", perZone);
+    perZone.slot_order.push("MUTATED");
+    expect(next.overrides.structure_overrides.top.slot_order).toEqual(["a"]);
+  });
+
+  it("seeds an empty structure_overrides on a fresh selection", () => {
+    const sel = createInitialUserSelection();
+    expect(sel.overrides.structure_overrides).toEqual({});
+  });
+});
+
+describe("Step-22 axes — applyPersistedNonFrameOverrides restore (IMP-56 u15)", () => {
+  it("layers persisted text_overrides through the u10 extract helper", () => {
+    const sel = makeSelection();
+    const next = applyPersistedNonFrameOverrides(sel, {
+      text_overrides: {
+        top: { "row_1_left_body.0": "복원" },
+      },
+    });
+    expect(next.overrides.text_overrides).toEqual({
+      top: { "row_1_left_body.0": "복원" },
+    });
+  });
+
+  it("layers persisted structure_overrides through the u10 extract helper", () => {
+    const sel = makeSelection();
+    const next = applyPersistedNonFrameOverrides(sel, {
+      structure_overrides: {
+        top: { slot_order: ["b", "a"], hidden_slots: ["c"] },
+      },
+    });
+    expect(next.overrides.structure_overrides).toEqual({
+      top: { slot_order: ["b", "a"], hidden_slots: ["c"] },
+    });
+  });
+
+  it("drops non-object payloads silently (no throw, axis stays empty)", () => {
+    const sel = makeSelection();
+    const next = applyPersistedNonFrameOverrides(sel, {
+      text_overrides: "garbage" as unknown as Record<string, Record<string, string>>,
+      structure_overrides: ["bad"] as unknown as Record<
+        string,
+        { slot_order?: string[]; hidden_slots?: string[] }
+      >,
+    });
+    expect(next.overrides.text_overrides).toEqual({});
+    expect(next.overrides.structure_overrides).toEqual({});
+  });
+});