refactor(tui): map every Action to its key surface

.github/copilot-instructions.md

@@ -294,10 +294,21 @@ directly, and TUI handlers adopt it as the conversion sub-PRs land
   `App::start_playback_uris` / `start_playback_context` /
   `start_playback_track_in_context` - never a hand-built
   `IoEvent::StartPlayback` in an arm.
-- No wildcard match arm anywhere under `src/core/action/`:
-  `wildcard_arms_in_action_tree` is pinned at 0 by a raw text scan that
-  includes tests, comments, and string literals. Write catch-all test arms
-  as `_other =>`.
+- No catch-all match arm under `src/core/action/` or in `tui/keymap.rs`:
+  both deny `clippy::wildcard_enum_match_arm` and
+  `clippy::match_wildcard_for_single_variants` (a named binding like
+  `_other =>` counts as a wildcard; `matches!` and `Option`/`Result`
+  scrutinees are exempt), and `wildcard_arms_in_action_tree` pins the
+  action tree at 0 by a raw text scan that includes tests, comments, and
+  string literals. CI clippy never compiles tests, so write a test
+  catch-all as `_other =>` and only on a `Result`/`Option` scrutinee.
+- Every `Action` variant has an arm in `tui/keymap.rs::default_binding`,
+  naming the key or gesture that produces it; a variant no gesture produces
+  is `Exposure::Unbound("reason")`. A new variant is a compile error until
+  it has an arm, and a test failure until `sample_actions()` in the same
+  file has a value for it (an `Unbound` one also goes into the `UNBOUND`
+  pin, which a producer scan of `src/tui/` checks). Feature-gate an arm's
+  body, never the arm: clippy skips a match when any arm carries a `#[cfg]`.
 - `Action` derives serde (the future frontend wire shape); a payload type
   added to it must stay serde-derivable.
 
@@ -374,8 +385,9 @@ Check `app.user_config.keys.<action>` instead of hard-coding key literals for
 global actions (`handle_app` in `src/tui/handlers/mod.rs`);
 `common_key_events::{up,down,left,right}_event` extend this to per-screen
 navigation. Adding a binding means fields on both `KeyBindings` and
-`KeyBindingsString` in `src/core/user_config.rs` plus a `help_entries` row in
-`src/tui/keymap.rs` with its `Requirement`.
+`KeyBindingsString` in `src/core/user_config.rs`, a `help_entries` row in
+`src/tui/keymap.rs` with its `Requirement`, and, when the key produces an
+`Action`, that variant's `default_binding` arm pointing at the new field.
 
 ### Requirements
 

AGENTS.md

@@ -296,10 +296,21 @@ directly, and TUI handlers adopt it as the conversion sub-PRs land
   `App::start_playback_uris` / `start_playback_context` /
   `start_playback_track_in_context` - never a hand-built
   `IoEvent::StartPlayback` in an arm.
-- No wildcard match arm anywhere under `src/core/action/`:
-  `wildcard_arms_in_action_tree` is pinned at 0 by a raw text scan that
-  includes tests, comments, and string literals. Write catch-all test arms
-  as `_other =>`.
+- No catch-all match arm under `src/core/action/` or in `tui/keymap.rs`:
+  both deny `clippy::wildcard_enum_match_arm` and
+  `clippy::match_wildcard_for_single_variants` (a named binding like
+  `_other =>` counts as a wildcard; `matches!` and `Option`/`Result`
+  scrutinees are exempt), and `wildcard_arms_in_action_tree` pins the
+  action tree at 0 by a raw text scan that includes tests, comments, and
+  string literals. CI clippy never compiles tests, so write a test
+  catch-all as `_other =>` and only on a `Result`/`Option` scrutinee.
+- Every `Action` variant has an arm in `tui/keymap.rs::default_binding`,
+  naming the key or gesture that produces it; a variant no gesture produces
+  is `Exposure::Unbound("reason")`. A new variant is a compile error until
+  it has an arm, and a test failure until `sample_actions()` in the same
+  file has a value for it (an `Unbound` one also goes into the `UNBOUND`
+  pin, which a producer scan of `src/tui/` checks). Feature-gate an arm's
+  body, never the arm: clippy skips a match when any arm carries a `#[cfg]`.
 - `Action` derives serde (the future frontend wire shape); a payload type
   added to it must stay serde-derivable.
 
@@ -376,8 +387,9 @@ Check `app.user_config.keys.<action>` instead of hard-coding key literals for
 global actions (`handle_app` in `src/tui/handlers/mod.rs`);
 `common_key_events::{up,down,left,right}_event` extend this to per-screen
 navigation. Adding a binding means fields on both `KeyBindings` and
-`KeyBindingsString` in `src/core/user_config.rs` plus a `help_entries` row in
-`src/tui/keymap.rs` with its `Requirement`.
+`KeyBindingsString` in `src/core/user_config.rs`, a `help_entries` row in
+`src/tui/keymap.rs` with its `Requirement`, and, when the key produces an
+`Action`, that variant's `default_binding` arm pointing at the new field.
 
 ### Requirements
 

CLAUDE.md

@@ -296,10 +296,21 @@ directly, and TUI handlers adopt it as the conversion sub-PRs land
   `App::start_playback_uris` / `start_playback_context` /
   `start_playback_track_in_context` - never a hand-built
   `IoEvent::StartPlayback` in an arm.
-- No wildcard match arm anywhere under `src/core/action/`:
-  `wildcard_arms_in_action_tree` is pinned at 0 by a raw text scan that
-  includes tests, comments, and string literals. Write catch-all test arms
-  as `_other =>`.
+- No catch-all match arm under `src/core/action/` or in `tui/keymap.rs`:
+  both deny `clippy::wildcard_enum_match_arm` and
+  `clippy::match_wildcard_for_single_variants` (a named binding like
+  `_other =>` counts as a wildcard; `matches!` and `Option`/`Result`
+  scrutinees are exempt), and `wildcard_arms_in_action_tree` pins the
+  action tree at 0 by a raw text scan that includes tests, comments, and
+  string literals. CI clippy never compiles tests, so write a test
+  catch-all as `_other =>` and only on a `Result`/`Option` scrutinee.
+- Every `Action` variant has an arm in `tui/keymap.rs::default_binding`,
+  naming the key or gesture that produces it; a variant no gesture produces
+  is `Exposure::Unbound("reason")`. A new variant is a compile error until
+  it has an arm, and a test failure until `sample_actions()` in the same
+  file has a value for it (an `Unbound` one also goes into the `UNBOUND`
+  pin, which a producer scan of `src/tui/` checks). Feature-gate an arm's
+  body, never the arm: clippy skips a match when any arm carries a `#[cfg]`.
 - `Action` derives serde (the future frontend wire shape); a payload type
   added to it must stay serde-derivable.
 
@@ -376,8 +387,9 @@ Check `app.user_config.keys.<action>` instead of hard-coding key literals for
 global actions (`handle_app` in `src/tui/handlers/mod.rs`);
 `common_key_events::{up,down,left,right}_event` extend this to per-screen
 navigation. Adding a binding means fields on both `KeyBindings` and
-`KeyBindingsString` in `src/core/user_config.rs` plus a `help_entries` row in
-`src/tui/keymap.rs` with its `Requirement`.
+`KeyBindingsString` in `src/core/user_config.rs`, a `help_entries` row in
+`src/tui/keymap.rs` with its `Requirement`, and, when the key produces an
+`Action`, that variant's `default_binding` arm pointing at the new field.
 
 ### Requirements
 

src/core/action/mod.rs

@@ -21,14 +21,20 @@
 //! - Playback starts go through `App::start_playback_uris` /
 //!   `App::start_playback_context`; no arm builds a `StartPlayback` event
 //!   by hand.
-//! - Matches in this module are exhaustive. The
-//!   `wildcard_arms_in_action_tree` gate keeps the catch-all arm count at
-//!   zero, tests included.
+//! - Matches in this module are exhaustive: the deny below refuses a
+//!   catch-all arm, and the `wildcard_arms_in_action_tree` gate keeps the
+//!   count at zero, tests included.
 //! - Address by identity (URIs, ids, names), never by list ordinal.
 //!
 //! The serde derives are the wire shape for future frontend codegen; they
 //! are deliberately in place before any second frontend consumes them.
 
+// The compiler half of the catch-all gate: a new variant must be placed.
+#![deny(
+  clippy::wildcard_enum_match_arm,
+  clippy::match_wildcard_for_single_variants
+)]
+
 use serde::{Deserialize, Serialize};
 
 use crate::core::app::DiscoverTimeRange;

src/infra/scripting/CLAUDE.md

@@ -4,7 +4,9 @@ Plugins never see `&mut App` or rspotify types: reads are cached serde snapshots
 from `src/core/plugin_api.rs`; writes are shared-vocabulary `Action`s
 (`src/core/action/`) the engine drains through `App::apply` while holding
 `&mut App`, each routed through the same `App` method the equivalent keybinding
-uses. Snapshot changes must be additive (`#[serde(default)]`, new keys
-only) - removing/renaming a key breaks installed plugins and requires bumping
+uses, where the terminal has one (`default_binding` in `src/tui/keymap.rs`
+records which variants have none). Snapshot changes must be additive
+(`#[serde(default)]`, new keys only) - removing/renaming a key breaks
+installed plugins and requires bumping
 `API_VERSION` and updating `docs/scripting.md`. Validation lives in
 `scripting/api.rs`; a failing callback is disabled on one strike.

src/tui/handlers/mod.rs

@@ -176,7 +176,7 @@ pub fn handle_app(key: Key, app: &mut App) {
   if key_matches_open_settings_binding(key, app.user_config.keys.open_settings)
     || key_matches_open_settings_binding(key, effective_open_settings)
   {
-    app.open_settings_screen();
+    app.apply(Action::Navigate(NavTarget::Settings));
     return;
   }