docs(openspec): archive android-auto-eq-presets

Merges its delta requirements into the android-auto-media base spec.

openspec/specs/android-auto-media/spec.md

@@ -62,14 +62,14 @@ The system MUST produce a browsable tree that never presents a user-selectable f
 
 ### Requirement: Browsable Media Tree
 
-`getChildren` MUST return a browsable tree rooted at `AudioService.browsableRootId`, organized into non-playable folders (Favoritos, Todas las emisoras, Mis emisoras) containing playable station items. Playable station items SHOULD carry an audio-quality subtitle when known. The `Favoritos` folder additionally MAY contain non-playable favorite-group sub-folders (see "Favorite Group Sub-Folders"); `Todas las emisoras` and `Mis emisoras` remain flat, unchanged by this capability.
-(Previously: `Favoritos` was a flat folder of playable station items only, with no sub-folder nesting.)
+`getChildren` MUST return a browsable tree rooted at `AudioService.browsableRootId`, organized into non-playable folders (Favoritos, Todas las emisoras, Mis emisoras, Ecualizador) containing playable items. Playable station items SHOULD carry an audio-quality subtitle when known. The `Favoritos` folder additionally MAY contain non-playable favorite-group sub-folders (see "Favorite Group Sub-Folders"); `Todas las emisoras` and `Mis emisoras` remain flat. The `Ecualizador` folder is flat, non-playable, and contains only the 6 fixed EQ preset items (see "EQ Preset Browsable Folder").
+(Previously: root contained exactly 3 folders — Favoritos, Todas las emisoras, Mis emisoras — with no EQ folder; Favoritos was a flat folder of playable station items only, with no sub-folder nesting.)
 
 #### Scenario: Car requests the root
 
 - GIVEN the car head unit connects and requests the root (`AudioService.browsableRootId`)
 - WHEN `getChildren` is called with the root id
-- THEN it returns three folder `MediaItem`s (Favoritos, Todas las emisoras, Mis emisoras), each with `playable: false`
+- THEN it returns four folder `MediaItem`s (Favoritos, Todas las emisoras, Mis emisoras, Ecualizador), each with `playable: false`
 
 #### Scenario: Car requests a folder with no stations
 
@@ -103,6 +103,74 @@ The system MUST produce a browsable tree that never presents a user-selectable f
 - THEN that station appears as a playable `emisora:<uuid>` item in exactly the same folder(s), position (subject to existing sort rules), title, art, and subtitle as it did before favorite-group folders were introduced
 - AND its presence and shape are unaffected by the existence, emptiness, or content of any favorite group
 
+### Requirement: EQ Preset Browsable Folder
+
+The Android Auto browse tree MUST expose the 6 fixed EQ presets (`PresetEcualizador.presets`) as playable items inside the `Ecualizador` root folder, each using a distinct `eq_preset:<nombre>` media-id scheme, separate from `emisora:<uuid>` and `grupo:<id>`.
+
+#### Scenario: Car requests the Ecualizador folder
+
+- GIVEN the `Ecualizador` folder id was returned under the root
+- WHEN `getChildren` is called with the `Ecualizador` folder id
+- THEN it returns exactly 6 playable `MediaItem`s, one per `PresetEcualizador.presets` entry, titled with the preset's name
+- AND each item's id is `eq_preset:<nombre>`, where `<nombre>` is that preset's unique name
+
+### Requirement: EQ Preset Selection Applies Without Disturbing Playback
+
+Selecting an `eq_preset:<nombre>` item MUST apply that preset immediately through the headless-safe EQ seam (e.g. `PluriWaveAudioHandler.aplicarPreset`), via a branch in `playFromMediaId` intercepted BEFORE the `emisora:`/`grupo:` routing. It MUST NOT call `playMediaItem`, MUST NOT mutate the now-playing `mediaItem`, and MUST NOT start, stop, restart, or otherwise alter current playback or playback position.
+
+#### Scenario: User selects a preset while a station is playing
+
+- GIVEN a station is currently playing and projected to the car
+- WHEN the user taps an `eq_preset:<nombre>` item, resolved via `playFromMediaId`
+- THEN the matching preset is applied via the headless-safe apply seam
+- AND the currently playing station continues uninterrupted, with no change to playback position or now-playing metadata
+
+#### Scenario: User selects a preset while nothing is playing
+
+- GIVEN no station is currently playing
+- WHEN the user taps an `eq_preset:<nombre>` item
+- THEN the matching preset is applied via the headless-safe apply seam
+- AND no playback starts as a result of the selection
+
+#### Scenario: Unknown or stale preset id
+
+- GIVEN `playFromMediaId` receives an `eq_preset:<nombre>` id whose `<nombre>` matches no entry in the current `PresetEcualizador.presets`
+- WHEN resolution fails to find a matching preset
+- THEN the selection is a no-op: no preset is applied, no playback state changes, and no unhandled exception propagates from the handler
+
+### Requirement: EQ Preset Persistence and Phone/Car Parity
+
+An EQ preset applied from the car MUST persist as the principal preset, with the same observable outcome as the phone's existing `ServicioEcualizador.guardarPrincipal`/`cambiarPresetPrincipal` path, and MUST be reflected on the phone. A principal preset changed on the phone MUST be observable from the car. The exact code path used to reach the headless-safe persistence seam from an Android Auto bind is deferred to `sdd-design`.
+
+#### Scenario: Preset applied from the car persists for the phone
+
+- GIVEN the user selects `eq_preset:<nombre>` from the car head unit
+- WHEN the selection is processed
+- THEN the preset is persisted as the principal preset
+- AND opening the phone's EQ UI afterward shows that preset as the active/principal preset
+
+#### Scenario: Preset applied from the phone is reflected for the car
+
+- GIVEN the user changes the principal preset from the phone UI
+- WHEN the car head unit subsequently observes EQ-related state through the browse/selection surface
+- THEN the car-observable state reflects the phone's most recently applied principal preset
+
+### Requirement: Active Preset Indication (Optional)
+
+The system MAY indicate the active/principal preset within the `Ecualizador` folder's rows. Because the legacy `MediaBrowserService` browsable-item model has no native "selected item" affordance, any indication, if implemented, MUST be conveyed via a row `title` text convention (e.g. a marker prefix/suffix) rather than assuming a checkmark or selection icon exists. If a reliable title-text convention is too costly to maintain, this requirement MAY instead be satisfied by explicitly not implementing active-preset indication.
+
+#### Scenario: Active preset is indicated via title convention (if implemented)
+
+- GIVEN the currently applied principal preset is known when `Ecualizador`'s children are built
+- WHEN the design's chosen title-text convention is applied
+- THEN exactly one of the 6 preset rows' `title` carries the active-preset marker, uniquely identifying that preset among the 6
+
+#### Scenario: Active preset indication is out of scope (if not implemented)
+
+- GIVEN the design opts not to implement an active-preset marker
+- WHEN the `Ecualizador` folder's children are built
+- THEN all 6 preset rows are returned with their plain preset names, with no partial or inconsistent marking applied
+
 ### Requirement: Playable Item Metadata
 
 Every playable `MediaItem` (station) MUST include a non-empty `title` and a loadable `artUri`. Stations without a logo MUST fall back to on-brand artwork, and stations whose logo URL cannot actually be loaded MUST degrade to the same on-brand fallback instead of rendering broken or blank art. The fallback MUST be visually consistent with the phone UI's per-station rotation rather than a generic launcher-icon copy.