feat: expose stable journey intent signals

tests/unit/SceneCanvas.test.ts

@@ -28,6 +28,11 @@ const journey = (
   chapter: "infrastructure",
   sign: null,
   arrived: false,
+  sectionActivation: {
+    layoutRevision: 0,
+    activeHeadingOffsetVh: 0,
+    nextHeadingOffsetVh: null,
+  },
   ...overrides,
 });
 

tests/unit/navigation-controller.test.ts

@@ -3,6 +3,7 @@ import {
   canonicalSectionIdFromHash,
   createNavigationController,
   validateSectionAnchor,
+  type NavigationState,
   type NavigationRuntime,
 } from "@/journey/navigation-controller";
 import type { SectionId } from "@/content/types";
@@ -205,6 +206,7 @@ describe("navigation epochs and effects", () => {
     expect(controller.state()).toEqual({
       epoch: 2,
       source: "passive-scroll",
+      phase: "idle",
       destinationId: null,
       signDestinationId: null,
     });
@@ -221,6 +223,30 @@ describe("navigation epochs and effects", () => {
     expect(harness.focused).toEqual(["experience"]);
   });
 
+  it("publishes travelling and settled only for the latest explicit epoch", () => {
+    const harness = createRuntime(true);
+    const controller = createNavigationController(sectionIds, harness.runtime);
+    const states: NavigationState[] = [];
+    controller.subscribe((state) => states.push(state));
+
+    controller.navigate("contact", target("contact"));
+    controller.navigate("toolkit", target("toolkit"));
+    expect(controller.state()).toMatchObject({
+      epoch: 2,
+      source: "explicit-navigation",
+      phase: "travelling",
+      destinationId: "toolkit",
+    });
+
+    harness.emitScrollEnd();
+    expect(controller.state()).toMatchObject({
+      epoch: 2,
+      phase: "settled",
+      destinationId: "toolkit",
+    });
+    expect(states.filter((state) => state.phase === "settled")).toHaveLength(1);
+  });
+
   it("falls back to three consecutive sub-pixel-stable animation frames", () => {
     const harness = createRuntime(false);
     const controller = createNavigationController(sectionIds, harness.runtime);
@@ -271,7 +297,9 @@ describe("navigation epochs and effects", () => {
     const controller = createNavigationController(sectionIds, harness.runtime);
 
     expect(controller.initialize("toolkit", target("toolkit"))).toBe(1);
+    expect(controller.state()).toMatchObject({ phase: "settled" });
     expect(controller.restore("profile", target("profile"))).toBe(2);
+    expect(controller.state()).toMatchObject({ phase: "travelling" });
     harness.runFrame();
     expect(harness.pushes).toEqual([]);
     expect(harness.replacements).toEqual([]);
@@ -283,6 +311,7 @@ describe("navigation epochs and effects", () => {
     expect(controller.state()).toEqual({
       epoch: 2,
       source: "history-restoration",
+      phase: "settled",
       destinationId: "profile",
       signDestinationId: null,
     });

tests/unit/scene-lifecycle.test.ts

@@ -582,6 +582,11 @@ function journey(overrides: Partial<JourneySnapshot> = {}): JourneySnapshot {
     chapter: 'deep-night',
     sign: null,
     arrived: false,
+    sectionActivation: {
+      layoutRevision: 0,
+      activeHeadingOffsetVh: 0,
+      nextHeadingOffsetVh: null,
+    },
     ...overrides,
   };
 }

tests/unit/scroll-drive-controller.test.ts

@@ -465,6 +465,7 @@ describe('useScrollDrive', () => {
     const navigation = shallowRef({
       epoch: 0,
       source: 'passive-scroll' as const,
+      phase: 'idle' as const,
       destinationId: null,
       signDestinationId: null,
     });

tests/unit/section-controller.test.ts

@@ -1,6 +1,7 @@
 import { describe, expect, it } from "vitest";
 import {
   activationLineDocumentY,
+  deriveSectionActivationSnapshot,
   deriveSectionState,
   isAtDocumentEnd,
   selectActiveSection,
@@ -109,6 +110,41 @@ describe("active section selection", () => {
     ).toBe("profile");
   });
 
+  it("derives responsive heading offsets from the same activation-line geometry", () => {
+    expect(deriveSectionActivationSnapshot({
+      headings: [
+        { id: "start", top: 100 },
+        { id: "profile", top: 420 },
+        { id: "experience", top: 1_120 },
+      ],
+      activeSectionId: "profile",
+      activationY: 500,
+      viewportHeight: 800,
+      layoutRevision: 7,
+    })).toEqual({
+      layoutRevision: 7,
+      activeHeadingOffsetVh: -0.1,
+      nextHeadingOffsetVh: 0.775,
+    });
+  });
+
+  it("returns no following-heading offset for the final active heading", () => {
+    expect(deriveSectionActivationSnapshot({
+      headings: [
+        { id: "start", top: 100 },
+        { id: "profile", top: 420 },
+      ],
+      activeSectionId: "profile",
+      activationY: 500,
+      viewportHeight: 800,
+      layoutRevision: 8,
+    })).toEqual({
+      layoutRevision: 8,
+      activeHeadingOffsetVh: -0.1,
+      nextHeadingOffsetVh: null,
+    });
+  });
+
   it("maps every canonical section to its chapter and arrival state", () => {
     expect([
       deriveSectionState("start"),