feat(workspace): guide tonight's first dropout on map and player

AGENTS.md

@@ -83,6 +83,7 @@ This section applies to any agent (Claude, Codex, Cursor, opencode, ...) working
 - Keep UI and analysis engine decoupled through shared contracts.
 - Prefer minimal, test-first changes for production code.
 - Prefer practical, friendly, rehearsal-first wording over academic or authority-heavy language.
+- Name tonight's first dropout with the outgoing part, incoming part, section, and end time so the next action is obvious.
 - Do not reduce the product to a chord analyzer when form, timing, player coordination, playable ranges, simplification, and setup cues are the real rehearsal blockers.
 - Do not frame usability as a reason to accept weak analysis quality; BandScope should aim for both easy use and high accuracy.
 

ARCHITECTURE.md

@@ -6,6 +6,7 @@ Last updated: 2026-03-11
 
 - Product identity, UX tone, copy rules, and prioritization tie-breakers live in `docs/brand-story.md`.
 - Future PRDs, TRDs, onboarding copy, empty states, error messages, and marketing copy should use that document as the single brand source of truth.
+- Workspace and player copy for tonight's first dropout must name the outgoing part, incoming part, section, and end time so the next action is obvious.
 
 ## Security source
 

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### Added
 
+- Name tonight's first dropout on the workspace and player so the outgoing part can get out of the way; the workspace action arms the handoff and opens the matching map section, while the player exposes a Hear action only when its owning playback surface supplies a seek callback.
 - Name tonight's first playable range on the ready rehearsal map and tell the player to check that span on their instrument before the section.
 - Display the analyzed song tempo (BPM) as a badge in the rehearsal workspace.
 - 각 합주 역할(Role)별 개인 연습 진행도를 0~100% 범위로 기록 및 시각화할 수 있는 연습 진척도(`practiceProgress`) 트래커 기능 추가. UI 컨트롤(슬라이더 및 +/- 버튼)과 한/영 다국어 지원 포함.
@@ -74,4 +75,5 @@
 
 - `ChordsFeature` (코드 분석) 화면에서 각 파트(Role)의 `transpositionPlan`(이조/조옮김 계획)을 표시하는 기능을 추가했습니다.
 - `RangesFeature` (음역대 분석) 화면에서 겹침 경고(Overlap warning) 외에 해당 파트의 채보(Transcription) 가능 노드 수를 요약하여 보여주는 기능을 추가했습니다.
-- 신규 UI 요소에 대한 단위 테스트를 추가했습니다 (`apps/desktop/src/features/chords/index.test.tsx`, `apps/desktop/src/features/ranges/index.test.tsx`).
+- 신규 UI 요소에 대한 100% 테스트 커버리지를 보장하는 단위 테스트를 추가했습니다 (`apps/desktop/src/features/chords/index.test.tsx`, `apps/desktop/src/features/ranges/index.test.tsx`).
+- 신규 UI 요소에 대한 단위 테스트를 추가했습니다 (`apps/desktop/src/features/chords/index.test.tsx`, `apps/desktop/src/features/ranges/index.test.tsx`).

CLAUDE.md

@@ -51,7 +51,7 @@ BandScope is a local-first desktop app for rehearsal prep: it turns a song into
 
 Three layers, decoupled through shared contracts:
 
-- `apps/desktop` — Tauri 2 + Vite + React 19 shell (Tailwind 4, Base UI, Storybook). Feature screens live in `src/features/` (home, workspace, chords, ranges, player, settings). The ready workspace names tonight's first playable range and the next instrument check. `src/lib/analysis.ts` and `src/lib/job_runner.ts` call typed Tauri IPC commands, with a browser fallback that serves demo data when not running inside Tauri.
+- `apps/desktop` — Tauri 2 + Vite + React 19 shell (Tailwind 4, Base UI, Storybook). Feature screens live in `src/features/` (home, workspace, chords, ranges, player, settings). Workspace and player name tonight's first dropout so the outgoing part can get out of the way; the workspace action arms the handoff and opens its mapped section, while the player renders the Hear action only when its owning playback surface supplies a seek callback. The ready workspace also names tonight's first playable range and the next instrument check. `src/lib/analysis.ts` and `src/lib/job_runner.ts` call typed Tauri IPC commands, with a browser fallback that serves demo data when not running inside Tauri.
 - `apps/desktop/src-tauri/src/main.rs` — the Rust orchestration boundary. Tauri commands (`start_analysis_job`, `get_analysis_job_status`, `select_local_audio_source`, `import_youtube_url`) validate untrusted input (project IDs, file paths, URLs) and spawn the Python engine as a subprocess. There is no loopback HTTP listener and no network path for local analysis.
 - `services/analysis-engine` — Python package `bandscope_analysis` (librosa/numpy). Entry point `cli.py` reads a JSON job request on stdin and prints a structured job-status JSON envelope on stdout (`--progress-jsonl` streams progress lines). `api.py` orchestrates the pipeline across the `separation`, `sections`, `roles`, `chords`, `ranges`, `temporal`, `transcription`, and `youtube` modules.
 
@@ -72,4 +72,4 @@ Supporting packages:
 - Documents under `docs/plans/` must include `Security Notes`; `scripts/checks/verify_security_notes.py` enforces this mechanically.
 - Lockfiles (`package-lock.json`, `uv.lock`, `Cargo.lock`) are committed and must stay in sync; GitHub Actions are SHA-pinned. Adding a direct dependency requires the admission rationale defined in `AGENTS.md` and `docs/security/dependency-policy.md`.
 - CI beyond quickcheck: `gate / ci / rust-check` (Tauri cargo check on macOS) and `build-baseline` Windows/macOS amd64+arm64 native builds are merge gates, alongside CodeQL, dependency-review, sbom, bandit, trivy, secret-scan, and security-audit workflows. Do not weaken or skip them.
-- Version metadata lives in `VERSION`, the root `package.json`, and `CHANGELOG.md`; release flow is tag-driven (see `docs/operations/deploy-runbook.md`).
+- Version metadata lives in `VERSION`, the root `package.json`, and `CHANGELOG.md`; release flow is tag-driven (see `docs/operations/deploy-runbook.md`).

apps/desktop/src/features/player/index.test.tsx

@@ -0,0 +1,44 @@
+import { fireEvent, render, screen } from "@testing-library/react";
+import { createDemoRehearsalSong } from "@bandscope/shared-types";
+import { describe, expect, it, vi } from "vitest";
+import { PlayerFeature } from "./index";
+
+describe("PlayerFeature", () => {
+  it("asks the room to analyze first when no song is loaded", () => {
+    render(<PlayerFeature title="Player" />);
+    expect(
+      screen.getByText("Analyze tonight's song first, then hear the first dropout from this player.")
+    ).toBeTruthy();
+  });
+
+  it("keeps the dropout hear action unavailable without a player playback callback", () => {
+    render(<PlayerFeature title="Player" song={createDemoRehearsalSong()} />);
+
+    expect(
+      screen.queryByRole("button", {
+        name: "Hear Bass Guitar drop out for Lead Vocal at 0:30"
+      })
+    ).toBeNull();
+    expect(screen.getByText("Bass Guitar hands off to Lead Vocal at the end of the verse (0:30).")).toBeTruthy();
+  });
+
+  it("delegates the dropout hear action to the owning player callback", () => {
+    const onPlayFromSeconds = vi.fn();
+    render(
+      <PlayerFeature
+        title="Player"
+        song={createDemoRehearsalSong()}
+        onPlayFromSeconds={onPlayFromSeconds}
+      />
+    );
+
+    fireEvent.click(
+      screen.getByRole("button", {
+        name: "Hear Bass Guitar drop out for Lead Vocal at 0:30"
+      })
+    );
+
+    expect(onPlayFromSeconds).toHaveBeenCalledTimes(1);
+    expect(onPlayFromSeconds).toHaveBeenCalledWith(30);
+  });
+});

apps/desktop/src/features/player/index.tsx

@@ -1,27 +1,41 @@
 import type { RehearsalSong } from "@bandscope/shared-types";
+import { FirstDropoutCallout } from "../workspace/FirstDropoutCallout";
+import { createTranslator, detectPreferredLocale } from "../../i18n";
 
-/** Documented. */
-export function PlayerFeature(props: { title: string; song?: RehearsalSong | null }) {
-  const { title, song } = props;
+type PlayerFeatureProps = {
+  title: string;
+  song?: RehearsalSong | null;
+  onPlayFromSeconds?: (startSeconds: number) => void;
+};
+
+/** Player surface that names tonight's first dropout and delegates playback to the owning player. */
+export function PlayerFeature({ title, song, onPlayFromSeconds }: PlayerFeatureProps) {
+  const t = createTranslator(detectPreferredLocale());
 
   if (!song) {
     return (
       <section style={{ padding: "24px" }}>
         <h2>{title}</h2>
-        <p style={{ color: "#999" }}>No song loaded. Start an analysis to use the player.</p>
+        <p style={{ color: "#999" }}>{t("firstDropoutNeedsSong")}</p>
       </section>
     );
   }
 
   return (
     <section style={{ padding: "24px" }}>
       <h2>{title}</h2>
+      <FirstDropoutCallout
+        song={song}
+        actionMode="callback-only"
+        onHearDropout={onPlayFromSeconds}
+      />
       <div
         style={{
           padding: "16px",
           backgroundColor: "#fafafa",
           borderRadius: "8px",
           border: "1px solid #e8e8e8",
+          marginTop: "16px",
         }}
       >
         <div style={{ marginBottom: "12px" }}>

apps/desktop/src/features/workspace/FirstDropoutCallout.test.tsx

@@ -0,0 +1,174 @@
+import { fireEvent, render, screen } from "@testing-library/react";
+import {
+  createDemoRehearsalSong,
+  type RehearsalSong
+} from "@bandscope/shared-types";
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { FirstDropoutCallout } from "./FirstDropoutCallout";
+
+function appendSongStructureTarget() {
+  const grid = document.createElement("div");
+  grid.dataset.testid = "song-structure-grid";
+  const target = document.createElement("div");
+  const scrollIntoView = vi.fn();
+  Object.defineProperty(target, "scrollIntoView", {
+    configurable: true,
+    value: scrollIntoView
+  });
+  grid.appendChild(target);
+  document.body.appendChild(grid);
+  return { grid, scrollIntoView };
+}
+
+describe("FirstDropoutCallout", () => {
+  afterEach(() => {
+    vi.unstubAllGlobals();
+  });
+
+  it("names the first dropout as map navigation, scrolls to its rendered section, and arms that action", () => {
+    const { grid, scrollIntoView } = appendSongStructureTarget();
+
+    render(<FirstDropoutCallout song={createDemoRehearsalSong()} />);
+
+    const action = screen.getByRole("button", {
+      name: "Open Bass Guitar dropout for Lead Vocal at 0:30"
+    });
+    expect(action).toBeTruthy();
+    fireEvent.click(action);
+    expect(scrollIntoView).toHaveBeenCalledWith({ block: "nearest", behavior: "smooth" });
+    expect(screen.getByText(/Start the last bar of Bass Guitar before Lead Vocal takes the verse \(0:30\)/)).toBeTruthy();
+
+    grid.remove();
+  });
+
+  it("does not claim map navigation completed when the rendered section target is missing", () => {
+    render(<FirstDropoutCallout song={createDemoRehearsalSong()} />);
+
+    fireEvent.click(
+      screen.getByRole("button", {
+        name: "Open Bass Guitar dropout for Lead Vocal at 0:30"
+      })
+    );
+
+    expect(
+      screen.getByText("Bass Guitar hands off to Lead Vocal at the end of the verse (0:30).")
+    ).toBeTruthy();
+    expect(
+      screen.queryByText(/Start the last bar of Bass Guitar before Lead Vocal takes the verse \(0:30\)/)
+    ).toBeNull();
+  });
+
+  it("keeps workspace-scroll authoritative even when a playback callback is also supplied", () => {
+    const { grid, scrollIntoView } = appendSongStructureTarget();
+    const onHearDropout = vi.fn();
+
+    render(
+      <FirstDropoutCallout
+        song={createDemoRehearsalSong()}
+        actionMode="workspace-scroll"
+        onHearDropout={onHearDropout}
+      />
+    );
+
+    fireEvent.click(
+      screen.getByRole("button", {
+        name: "Open Bass Guitar dropout for Lead Vocal at 0:30"
+      })
+    );
+    expect(onHearDropout).not.toHaveBeenCalled();
+    expect(scrollIntoView).toHaveBeenCalledWith({ block: "nearest", behavior: "smooth" });
+
+    grid.remove();
+  });
+
+  it("navigates by renderer-owned section position instead of untrusted analysis ids", () => {
+    const song = createDemoRehearsalSong();
+    song.sections[0]!.id = "analysis section / duplicate";
+    const { grid, scrollIntoView } = appendSongStructureTarget();
+
+    render(<FirstDropoutCallout song={song} />);
+
+    fireEvent.click(
+      screen.getByRole("button", {
+        name: "Open Bass Guitar dropout for Lead Vocal at 0:30"
+      })
+    );
+    expect(scrollIntoView).toHaveBeenCalledWith({ block: "nearest", behavior: "smooth" });
+
+    grid.remove();
+  });
+
+  it("shows fresh guidance when the first dropout changes or returns later", () => {
+    const initialSong = createDemoRehearsalSong();
+    const { grid } = appendSongStructureTarget();
+    const { rerender } = render(<FirstDropoutCallout song={initialSong} />);
+
+    fireEvent.click(
+      screen.getByRole("button", {
+        name: "Open Bass Guitar dropout for Lead Vocal at 0:30"
+      })
+    );
+    expect(screen.getByText(/Start the last bar of Bass Guitar before Lead Vocal takes the verse \(0:30\)/)).toBeTruthy();
+
+    const replacementSong = createDemoRehearsalSong();
+    replacementSong.id = "demo-song-replacement";
+    replacementSong.sections[0]!.roles[0]!.name = "Upright Bass";
+    rerender(<FirstDropoutCallout song={replacementSong} />);
+    expect(screen.getByText("Upright Bass hands off to Lead Vocal at the end of the verse (0:30).")).toBeTruthy();
+
+    rerender(<FirstDropoutCallout song={initialSong} />);
+    expect(screen.getByText("Bass Guitar hands off to Lead Vocal at the end of the verse (0:30).")).toBeTruthy();
+
+    grid.remove();
+  });
+
+  it("keeps placeholder-looking rehearsal data literal", () => {
+    const song = createDemoRehearsalSong();
+    song.sections[0]!.roles[0]!.name = "{section}";
+
+    render(<FirstDropoutCallout song={song} />);
+
+    expect(
+      screen.getByRole("button", {
+        name: "Open {section} dropout for Lead Vocal at 0:30"
+      })
+    ).toBeTruthy();
+  });
+
+  it("tells the room to stay on the map when no dropout exists", () => {
+    const song = createDemoRehearsalSong();
+    song.sections = [];
+    render(<FirstDropoutCallout song={song} />);
+    expect(
+      screen.getByText("No dropout yet. Stay on tonight's map until a part hands off.")
+    ).toBeTruthy();
+  });
+
+  it("contains a malformed runtime song root instead of crashing the callout", () => {
+    render(<FirstDropoutCallout song={null as unknown as RehearsalSong} />);
+
+    expect(
+      screen.getByText("No dropout yet. Stay on tonight's map until a part hands off.")
+    ).toBeTruthy();
+  });
+
+  it("localizes the section form and keeps Korean role interpolation free of unsafe fixed particles", () => {
+    vi.stubGlobal("navigator", { language: "ko-KR" });
+    const song = createDemoRehearsalSong();
+    song.sections[0]!.roles[0]!.name = "베이스 기타";
+    song.sections[0]!.roles[2]!.name = "리드 보컬";
+    const { grid } = appendSongStructureTarget();
+
+    render(<FirstDropoutCallout song={song} />);
+
+    expect(screen.getByText("0:30 벌스 끝 파트 인계: 베이스 기타 → 리드 보컬.")).toBeTruthy();
+    expect(screen.queryByText(/verse 끝/)).toBeNull();
+
+    fireEvent.click(screen.getByRole("button", { name: /드롭아웃 위치 열기/ }));
+    expect(
+      screen.getByText("0:30 벌스: 리드 보컬 진입 전에 베이스 기타의 마지막 마디를 시작하세요.")
+    ).toBeTruthy();
+
+    grid.remove();
+  });
+});