feat: polish nightdrive road sun and signage

tests/unit/sign-controller.test.ts

@@ -101,16 +101,32 @@ describe('clock-driven sign lifecycle', () => {
     expect(controller.needsFrame()).toBe(true);
   });
 
-  it('cancels an unreadable sign on reverse and departs a readable sign cleanly', () => {
+  it('cancels a concealed sign on reverse and departs a visible approaching sign cleanly', () => {
     const early = createSignController();
     early.sample(sample());
-    expect(early.sample(sample({ now: 500, direction: -1, deltaY: -20 }))).toBeNull();
+    expect(early.sample(sample({ now: 310, direction: -1, deltaY: -20 }))).toBeNull();
     expect(early.needsFrame()).toBe(false);
 
     const readable = createSignController();
     readable.sample(sample());
-    readable.sample(sample({ now: 1_200, direction: 0 }));
-    expect(readable.sample(sample({ now: 1_500, direction: -1, deltaY: -20 }))).toMatchObject({
+    expect(readable.sample(sample({ now: 700, direction: -1, deltaY: -20 }))).toMatchObject({
+      phase: 'depart',
+      progress: 0,
+    });
+  });
+
+  it('preserves the minimum readable dwell when reverse input requests departure', () => {
+    const controller = createSignController();
+    controller.sample(sample());
+    controller.sample(sample({ now: 1_200, direction: 0 }));
+
+    expect(controller.sample(sample({ now: 1_500, direction: -1, deltaY: -20 }))).toMatchObject({
+      phase: 'dwell',
+    });
+    expect(controller.sample(sample({ now: 2_599, direction: 0, deltaY: 0 }))).toMatchObject({
+      phase: 'dwell',
+    });
+    expect(controller.sample(sample({ now: 2_600, direction: 0, deltaY: 0 }))).toMatchObject({
       phase: 'depart',
       progress: 0,
     });
@@ -132,18 +148,22 @@ describe('clock-driven sign lifecycle', () => {
   it.each([
     ['multiple crossed sections', { crossedBoundaries: 2 }],
     ['a jump over 0.75 viewport heights', { deltaY: 601 }],
-  ])('departs a readable stale sign cleanly after %s', (_label, overrides) => {
+  ])('coalesces %s while preserving the readable dwell', (_label, overrides) => {
     const controller = createSignController();
     controller.sample(sample());
     controller.sample(sample({ now: 1_200, direction: 0 }));
 
     expect(controller.sample(sample({ now: 1_400, ...overrides }))).toMatchObject({
+      targetId: 'profile',
+      phase: 'dwell',
+    });
+    expect(controller.needsFrame()).toBe(true);
+    expect(controller.sample(sample({ now: 2_600, direction: 0, deltaY: 0 }))).toMatchObject({
       targetId: 'profile',
       phase: 'depart',
       progress: 0,
       opacity: 1,
     });
-    expect(controller.needsFrame()).toBe(true);
   });
 
   it('departs when the authoritative section has already passed the latched target', () => {
@@ -161,6 +181,33 @@ describe('clock-driven sign lifecycle', () => {
     });
   });
 
+  it('does not truncate dwell when the authoritative section passes the target', () => {
+    const controller = createSignController();
+    controller.sample(sample());
+    controller.sample(sample({ now: 1_200, direction: 0 }));
+
+    expect(controller.sample(sample({
+      now: 1_350,
+      direction: 1,
+      activeSectionId: 'experience',
+      candidateId: 'infrastructure',
+    }))).toMatchObject({ targetId: 'profile', phase: 'dwell' });
+    expect(controller.sample(sample({
+      now: 2_599,
+      direction: 0,
+      deltaY: 0,
+      activeSectionId: 'experience',
+      candidateId: 'infrastructure',
+    }))).toMatchObject({ phase: 'dwell' });
+    expect(controller.sample(sample({
+      now: 2_600,
+      direction: 0,
+      deltaY: 0,
+      activeSectionId: 'experience',
+      candidateId: 'infrastructure',
+    }))).toMatchObject({ phase: 'depart', progress: 0 });
+  });
+
   it('retargets a changed far-away candidate only while the sign is concealed', () => {
     const controller = createSignController();
     controller.sample(sample());