Add in-app micro-feedback prompts for new features

Show a one-time toast asking how a feature is working after its third
successful use, with an optional comment sent anonymously to the Yaak
API (feature key, text, app version, and OS only — nothing identifying,
and nothing is sent unless the user clicks Send).

- New cmd_send_feedback Tauri command posts fire-and-forget via the
  shared API client (localhost in dev)
- Feature keys registry (cookie-editor, response-history, sse-summary,
  git-sync) with per-feature use counting in the key-value store
- "Never ask for feedback" setting to disable prompts entirely
- Toast gains dynamicHeight and hideDismiss props for richer content
- Fix missing vertical padding on xs/2xs multiline inputs
- Fix unused-import and dead-code warnings in yaak-system-appearance
  on non-Linux builds

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

crates/yaak-models/bindings/gen_models.ts

@@ -402,6 +402,7 @@ export type Settings = {
   themeLight: string;
   updateChannel: string;
   hideLicenseBadge: boolean;
+  hideFeedbackPrompts: boolean;
   autoupdate: boolean;
   autoDownloadUpdates: boolean;
   checkNotifications: boolean;

crates/yaak-models/migrations/20260704000000_hide-feedback-prompts.sql

@@ -0,0 +1,3 @@
+-- Add a setting to disable in-app feature feedback prompts
+ALTER TABLE settings
+    ADD COLUMN hide_feedback_prompts BOOLEAN DEFAULT FALSE NOT NULL;

crates/yaak-models/src/models.rs

@@ -246,6 +246,7 @@ pub struct Settings {
     pub theme_light: String,
     pub update_channel: String,
     pub hide_license_badge: bool,
+    pub hide_feedback_prompts: bool,
     pub autoupdate: bool,
     pub auto_download_updates: bool,
     pub check_notifications: bool,
@@ -303,6 +304,7 @@ impl UpsertModelInfo for Settings {
             (ThemeLight, self.theme_light.as_str().into()),
             (UpdateChannel, self.update_channel.into()),
             (HideLicenseBadge, self.hide_license_badge.into()),
+            (HideFeedbackPrompts, self.hide_feedback_prompts.into()),
             (Autoupdate, self.autoupdate.into()),
             (AutoDownloadUpdates, self.auto_download_updates.into()),
             (ColoredMethods, self.colored_methods.into()),
@@ -332,6 +334,7 @@ impl UpsertModelInfo for Settings {
             SettingsIden::ThemeLight,
             SettingsIden::UpdateChannel,
             SettingsIden::HideLicenseBadge,
+            SettingsIden::HideFeedbackPrompts,
             SettingsIden::Autoupdate,
             SettingsIden::AutoDownloadUpdates,
             SettingsIden::ColoredMethods,
@@ -372,6 +375,7 @@ impl UpsertModelInfo for Settings {
             autoupdate: row.get("autoupdate")?,
             auto_download_updates: row.get("auto_download_updates")?,
             hide_license_badge: row.get("hide_license_badge")?,
+            hide_feedback_prompts: row.get("hide_feedback_prompts")?,
             colored_methods: row.get("colored_methods")?,
             check_notifications: row.get("check_notifications")?,
             hotkeys: serde_json::from_str(&hotkeys).unwrap_or_default(),

crates/yaak-models/src/queries/settings.rs

@@ -38,6 +38,7 @@ impl<'a> ClientDb<'a> {
             autoupdate: true,
             colored_methods: false,
             hide_license_badge: false,
+            hide_feedback_prompts: false,
             auto_download_updates: true,
             check_notifications: true,
             hotkeys: HashMap::new(),