feat(plugins): add JSONForms-based plugin configuration UI (#4911)

* feat(plugins): add JSONForms schema for plugin configuration

Signed-off-by: Deluan <deluan@navidrome.org>

* feat: enhance error handling by formatting validation errors with field names

Signed-off-by: Deluan <deluan@navidrome.org>

* feat: enforce required fields in config validation and improve error handling

Signed-off-by: Deluan <deluan@navidrome.org>

* format JS code

Signed-off-by: Deluan <deluan@navidrome.org>

* feat: add config schema validation and enhance manifest structure

Signed-off-by: Deluan <deluan@navidrome.org>

* feat: refactor plugin config parsing and add unit tests

Signed-off-by: Deluan <deluan@navidrome.org>

* feat: add config validation error message in Portuguese

* feat: enhance AlwaysExpandedArrayLayout with description support and improve array control testing

Signed-off-by: Deluan <deluan@navidrome.org>

* feat: update Discord Rust plugin configuration to use JSONForm for user tokens and enhance schema validation

Signed-off-by: Deluan <deluan@navidrome.org>

* fix: resolve React Hooks linting issues in plugin UI components

* Apply suggestions from code review

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

* format code

Signed-off-by: Deluan <deluan@navidrome.org>

* feat: migrate schema validation to use santhosh-tekuri/jsonschema and improve error formatting

Signed-off-by: Deluan <deluan@navidrome.org>

* address PR comments

Signed-off-by: Deluan <deluan@navidrome.org>

* fix flaky test

Signed-off-by: Deluan <deluan@navidrome.org>

* feat: enhance array layout and configuration handling with AJV defaults

Signed-off-by: Deluan <deluan@navidrome.org>

* feat: implement custom tester to exclude enum arrays from AlwaysExpandedArrayLayout

Signed-off-by: Deluan <deluan@navidrome.org>

* feat: add error boundary for schema rendering and improve error messages

Signed-off-by: Deluan <deluan@navidrome.org>

* feat: refine non-enum array control logic by utilizing JSONForms schema resolution

Signed-off-by: Deluan <deluan@navidrome.org>

* feat: add error styling to ToggleEnabledSwitch for disabled state

Signed-off-by: Deluan <deluan@navidrome.org>

* feat: adjust label positioning and styling in SchemaConfigEditor for improved layout

Signed-off-by: Deluan <deluan@navidrome.org>

* feat: implement outlined input controls renderers to replace custom fragile CSS

Signed-off-by: Deluan <deluan@navidrome.org>

* feat: remove margin from last form control inside array items for better spacing

Signed-off-by: Deluan <deluan@navidrome.org>

* feat: enhance AJV error handling to transform required errors for field-level validation

Signed-off-by: Deluan <deluan@navidrome.org>

* feat: set default value for User Tokens in manifest.json to improve user experience

Signed-off-by: Deluan <deluan@navidrome.org>

* format

Signed-off-by: Deluan <deluan@navidrome.org>

* feat: add margin to outlined input controls for improved spacing

Signed-off-by: Deluan <deluan@navidrome.org>

* feat: remove redundant margin rule for last form control in array items

Signed-off-by: Deluan <deluan@navidrome.org>

* feat: adjust font size of label elements in SchemaConfigEditor for improved readability

Signed-off-by: Deluan <deluan@navidrome.org>

---------

Signed-off-by: Deluan <deluan@navidrome.org>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

tests/mock_plugin_manager.go

@@ -5,7 +5,7 @@ import (
 )
 
 // MockPluginManager is a mock implementation of plugins.PluginManager for testing.
-// It implements EnablePlugin, DisablePlugin, UpdatePluginConfig, UpdatePluginUsers, UpdatePluginLibraries and RescanPlugins methods.
+// It implements EnablePlugin, DisablePlugin, UpdatePluginConfig, ValidatePluginConfig, UpdatePluginUsers, UpdatePluginLibraries and RescanPlugins methods.
 type MockPluginManager struct {
 	// EnablePluginFn is called when EnablePlugin is invoked. If nil, returns EnableError.
 	EnablePluginFn func(ctx context.Context, id string) error
@@ -13,6 +13,8 @@ type MockPluginManager struct {
 	DisablePluginFn func(ctx context.Context, id string) error
 	// UpdatePluginConfigFn is called when UpdatePluginConfig is invoked. If nil, returns ConfigError.
 	UpdatePluginConfigFn func(ctx context.Context, id, configJSON string) error
+	// ValidatePluginConfigFn is called when ValidatePluginConfig is invoked. If nil, returns ValidateError.
+	ValidatePluginConfigFn func(ctx context.Context, id, configJSON string) error
 	// UpdatePluginUsersFn is called when UpdatePluginUsers is invoked. If nil, returns UsersError.
 	UpdatePluginUsersFn func(ctx context.Context, id, usersJSON string, allUsers bool) error
 	// UpdatePluginLibrariesFn is called when UpdatePluginLibraries is invoked. If nil, returns LibrariesError.
@@ -24,6 +26,7 @@ type MockPluginManager struct {
 	EnableError    error
 	DisableError   error
 	ConfigError    error
+	ValidateError  error
 	UsersError     error
 	LibrariesError error
 	RescanError    error
@@ -35,6 +38,10 @@ type MockPluginManager struct {
 		ID         string
 		ConfigJSON string
 	}
+	ValidatePluginConfigCalls []struct {
+		ID         string
+		ConfigJSON string
+	}
 	UpdatePluginUsersCalls []struct {
 		ID        string
 		UsersJSON string
@@ -75,6 +82,17 @@ func (m *MockPluginManager) UpdatePluginConfig(ctx context.Context, id, configJS
 	return m.ConfigError
 }
 
+func (m *MockPluginManager) ValidatePluginConfig(ctx context.Context, id, configJSON string) error {
+	m.ValidatePluginConfigCalls = append(m.ValidatePluginConfigCalls, struct {
+		ID         string
+		ConfigJSON string
+	}{ID: id, ConfigJSON: configJSON})
+	if m.ValidatePluginConfigFn != nil {
+		return m.ValidatePluginConfigFn(ctx, id, configJSON)
+	}
+	return m.ValidateError
+}
+
 func (m *MockPluginManager) UpdatePluginUsers(ctx context.Context, id, usersJSON string, allUsers bool) error {
 	m.UpdatePluginUsersCalls = append(m.UpdatePluginUsersCalls, struct {
 		ID        string