Refactor: remove desktop/Tauri bundle, add i18n, CI/CD pipeline

- Remove desktop (Tauri) bundle: docs/desktop.md, icons/, tauri.conf.json,
  src/desktop/mod.rs, gen/schemas/
- Remove build.rs (no longer needed)
- Add i18n system (crates/core-api, plugin-mobile-connector, web)
- Refactor config system (src/config.rs, boot_format.rs)
- Add mobile connector features (app, router, device pairing)
- Plugin system improvements (skald-core)
- Update dependencies (Cargo.lock, Cargo.toml)
- CI/CD: Gitea Actions workflows (nightly + release), package.sh,
  verify-version.sh, builds.skaldagent.net config

crates/core-api/src/i18n.rs

@@ -0,0 +1,55 @@
+//! Backend localization contract shared by the core and every plugin.
+//!
+//! Two halves:
+//! - [`LocaleBundle`] — what a plugin *declares* (its translation table for one
+//!   locale), returned from `Plugin::i18n()` and collected into a single catalog
+//!   at boot. Keys must be namespaced (`plugin.<id>.<key>`) so bundles from
+//!   different plugins — and the core — merge without clobbering each other, and
+//!   so the same key can back the frontend fragment's `t()` string.
+//! - [`I18nApi`] — what a plugin *calls* at request time to turn a key into text
+//!   for the caller. Injected into `PluginContext.i18n`; the concrete impl lives
+//!   in `skald-core` (it owns the locale-resolution chain and the system pool).
+//!
+//! The core never emits user-facing text through a hardcoded English literal
+//! once it can go through this seam — a plugin's own error/generated strings
+//! reach the user in the user's language, mirroring the frontend `i18n.js`.
+
+use std::collections::HashMap;
+
+use async_trait::async_trait;
+
+/// One namespace's translation table for a single locale, as declared by a
+/// plugin (or the core). Merged into the boot-time catalog keyed by locale;
+/// keys collide across bundles only if two authors reuse the same fully
+/// qualified key, which the `plugin.<id>.` convention prevents.
+#[derive(Debug, Clone)]
+pub struct LocaleBundle {
+    /// Locale code — `"en"`, `"it"`, `"fr"`. Must match a supported locale;
+    /// anything else is simply never selected by the resolver.
+    pub locale:  String,
+    /// Fully qualified key → translated string. Placeholders are `{name}`.
+    pub strings: HashMap<String, String>,
+}
+
+impl LocaleBundle {
+    pub fn new(locale: impl Into<String>, strings: HashMap<String, String>) -> Self {
+        Self { locale: locale.into(), strings }
+    }
+}
+
+/// Runtime translation, injected into [`crate::plugin::PluginContext`].
+///
+/// The catalog behind it is built once at boot from every plugin's
+/// `Plugin::i18n()`. Resolution mirrors the rest of the system: a user's
+/// `users.locale` override → the instance default → built-in English → the raw
+/// key as a last resort. Placeholders (`{name}`) are filled from `args`.
+#[async_trait]
+pub trait I18nApi: Send + Sync {
+    /// Translate `key` for `user_id`, resolving *their* effective locale. Use
+    /// this from any request/notification path where the target user is known.
+    async fn for_user(&self, user_id: &str, key: &str, args: &[(&str, &str)]) -> String;
+
+    /// Translate for an already-resolved locale — for contexts with no single
+    /// user (boot logs, broadcast copy) that have decided a locale by other means.
+    fn get(&self, locale: &str, key: &str, args: &[(&str, &str)]) -> String;
+}

crates/core-api/src/lib.rs

@@ -9,6 +9,7 @@ pub mod chatbot;
 pub mod chat_hub;
 pub mod command;
 pub mod events;
+pub mod i18n;
 pub mod image_generate;
 pub mod inbox;
 pub mod interface_tool;

crates/core-api/src/plugin.rs

@@ -7,6 +7,7 @@ use tokio::sync::RwLock;
 
 use crate::command::CommandApi;
 use crate::config_api::ConfigApi;
+use crate::i18n::I18nApi;
 use crate::system_bus::SystemEventBus;
 use crate::image_generate::ImageGenerateRegistry;
 use crate::location::LocationUpdater;
@@ -90,6 +91,10 @@ pub struct PluginContext {
     /// Per-user plugin configuration store (`plugin_user_configs` table).
     /// Admin-readable — never secrets.
     pub user_config:             Arc<dyn PluginUserConfigApi>,
+    /// Backend localization. Turns a plugin's namespaced string key into text in
+    /// the caller's language (`i18n.for_user(user_id, key, args)`). The catalog
+    /// is built at boot from every plugin's [`Plugin::i18n`]. See `core_api::i18n`.
+    pub i18n:                    Arc<dyn I18nApi>,
     pub web_port:                u16,
     pub remote_slot:             Arc<RwLock<Option<Arc<dyn RemoteAccess>>>>,
     pub router_factory:          RouterFactory,
@@ -174,7 +179,9 @@ pub trait Plugin: Send + Sync {
     ///   `/api/plugin/<id>/…` — no host APIs are injected;
     /// - it runs with the full privileges of the logged-in session (plugins are
     ///   trusted — they ship in the binary);
-    /// - it carries its own UI strings (reads the locale from `/api/auth/me`).
+    /// - it localizes by shipping its own `{en,it,fr}` string table and
+    ///   registering it via `addStrings` into the host's shared `i18n.js`, then
+    ///   using the same `t()`/`I18nMixin` (keys namespaced `plugin.<id>.`).
     ///
     /// Default: no pages.
     fn web_pages(&self) -> Vec<PluginPage> { Vec::new() }
@@ -192,6 +199,13 @@ pub trait Plugin: Send + Sync {
     /// is stopped. Default: no tools.
     fn tools(self: Arc<Self>) -> Vec<Arc<dyn crate::tool::Tool>> { Vec::new() }
 
+    /// Backend translation tables this plugin contributes — one
+    /// [`crate::i18n::LocaleBundle`] per locale it ships. Collected once at boot
+    /// into the shared catalog behind [`PluginContext::i18n`]. Keys must be
+    /// namespaced (`plugin.<id>.<key>`). Default: no strings (plugin emits no
+    /// localized backend text). See `core_api::i18n`.
+    fn i18n(&self) -> Vec<crate::i18n::LocaleBundle> { Vec::new() }
+
     /// Returns a [`Memory`] backend if this plugin provides one.
     fn memory(&self) -> Option<Arc<dyn Memory>> { None }