[Activation] Deliver a licensed demo song and measurable first-run rehearsal journey

[seonghobae]

Parent: #958
Baseline: #968

Buyer-visible gap

A buyer cannot evaluate BandScope from architecture documents, unit tests, or an empty workspace. The first launch must demonstrate the actual product value without requiring the user to locate a suitable song, understand MIR terminology, install an undocumented dependency, or guess the next action after analysis.

The live queue includes useful Storybook, empty/error, navigation, priority, first-part, loop, count-in, and cue slices (#897–#905 and related T3 work), but no single protected journey proves that a new musician reaches a useful rehearsal action with licensed, reproducible input.

Product outcome

A clean installation offers an optional, clearly licensed demo rehearsal and a parallel Use my own song path:

launch
→ choose demo or local file
→ choose role and rehearsal goal
→ analyze with honest stage progress and limitations
→ open the most important cue
→ loop or mark it for rehearsal
→ save and reopen the project

The demo must exercise the same production file validation, resource admission, decoding, analysis, rehearsal-player, persistence, and recovery boundaries as user audio.

Required scope

Licensed demo package

• Include or reproducibly acquire a redistributable song/fixture with explicit audio, stem, annotation, artwork, and attribution rights.
• Record source, author/performer credit, exact hashes, transformation history, license text, and permitted redistribution/evaluation uses.
• Use real decoded audio through the production boundary; do not substitute direct feature arrays or mocked browser success.
• Include ground-truth annotations sufficient to connect the demo to [Product Gap] Add real-audio MIR accuracy acceptance benchmarks #770 accuracy evidence.
• Keep private/commercial benchmark assets separate from the public demo.

First-run state machine

• Present Try the demo and Use my own song immediately and state the local-first privacy boundary in one action-oriented sentence.
• Ask only for information required to produce a useful result: intended role, optional skill level, and rehearsal goal.
• Detect missing runtime/model/backend prerequisites before expensive work and offer a supported recovery action.
• Show bounded, cancellable progress based on actual worker stages; never invent unsupported percentages.
• Land on one prioritized rehearsal action rather than a dense dashboard with no next step.
• Explain confidence, known limitations, and how the user can correct a role or section result.
• Allow experienced/returning users to skip onboarding and reopen recent projects.

Live PR convergence

• feat(workspace): Storybook tokens for rehearsal components #897 is the current executable Storybook/token slice.
• feat(workspace): put the next rehearsal action on empty and error cards #898 and feat(workspace): open existing rehearsal surfaces from the sidebar #899 own current empty/error and sidebar-navigation slices.
• feat(workspace): name tonight's export and priority actions #900 and feat(workspace): start tonight's first part from the ready board #901 own current priority/first-part slices.
• feat(workspace): loop tonight's first section on the map #903, feat(workspace): count in tonight's first section on the map #904, and feat(workspace): open tonight's first notes on the groove map #905 own current loop/count-in/first-notes slices but must converge behind [Product] Add an active rehearsal player with precise looping and role controls #961's active-player state machine.
• Other T3 cue PRs can contribute to the first rehearsal action only after [Engineering] Convert the open PR backlog into dependency-aware merge trains and product verticals #966 establishes their canonical stack/succession.
• Do not preserve multiple competing onboarding, activation, or action-completion stores.

Activation evidence

• Define local activation milestones without collecting audio, project content, paths, URLs, or identity.
• Keep evidence local by default; optional aggregate telemetry requires explicit enablement and the privacy/diagnostics contract in [Operations] Build redacted diagnostics, crash evidence and an offline support bundle #963.
• Measure at minimum:
  • first launch success;
  • demo/local-file choice;
  • first valid audio acceptance;
  • analysis started/completed/cancelled/failed by stage;
  • first cue opened;
  • first rehearsal action completed;
  • project saved and reopened.
• Measure time-to-first-rehearsal before declaring a release threshold; do not invent a target from synthetic success.

Acceptance criteria

• Clean supported Windows and macOS installations complete the demo journey without a terminal, external account, or undocumented dependency.
• Demo audio/artwork/annotations have a checked license/provenance manifest and immutable hashes.
• Demo and user audio use the same production intake, resource, decode, analysis, player, project, and recovery boundaries.
• A measured time-to-first-rehearsal distribution is published before a release gate is chosen.
• Every failure state provides a concrete next action and preserves retry, choose-another-file, demo, and support-evidence paths.
• Keyboard-only and screen-reader users complete the entire journey.
• Korean and English preserve the same choices, limitations, privacy statements, and actions.
• Local activation evidence excludes audio, lyrics, project payloads, paths, URLs, and identity.
• First-run state resumes safely after restart and never traps a returning user.
• Repository-owned production statement/branch coverage and public API documentation remain 100%.
• Current-head CI, security, license, accessibility, qualifying independent approval, zero unresolved actionable threads, and branch protection pass without bypass.

Real-world personas and failures

• first-time singer unfamiliar with MIR terminology;
• bassist selecting a role weakly represented in the mix;
• keyboard-only and screen-reader users;
• offline user after installation;
• unsupported codec selected before choosing the demo;
• low-memory device triggering resource admission/fallback;
• analysis cancelled and resumed;
• corrupt or missing demo asset;
• returning user skipping onboarding and reopening a project.

Non-goals

• No mandatory account creation or cloud upload.
• No telemetry consent hidden in general terms.
• No copyrighted commercial song committed without redistribution rights.
• No synthetic or mocked result presented as production analysis success.
• No onboarding copy that promises universal musical correctness.

[seonghobae]

First-run empty-card slice is on #980 (feat/first-run-use-own-song @ a6d5b6f5d2191245c5a52c4af0a7cd4e67c2200a). The empty workspace now names Use my own song as the next action. A licensed demo package is still not bundled and remains later #964 work. This does not replace #974 (analyze after a song is already selected).