feat: universal LLM gateway with embedded multilingual admin console

- OpenAI-compatible gateway with intelligent routing via cortiq-router (allaigate)
- Embedded build-free admin SPA at /admin: 7 languages (en/ru/de/fr/es/zh/tr),
  light/dark themes, hot config reload (no restart)
- Admin API, per-request statistics + Prometheus /metrics, secret store, playground
- English documentation (primary) with Russian translations (*.ru.md)

src/state.rs

@@ -0,0 +1,107 @@
+//! Shared gateway state accessible across all request handlers.
+//!
+//! The config-derived part (`Live`) lives behind an `ArcSwap`, which allows
+//! hot-reloading the model pool, routing table, and router connection without
+//! a restart: the admin API validates the new config, builds a new `Live`,
+//! atomically writes the TOML, and swaps the pointer.
+
+use crate::config::Config;
+use crate::registry::Registry;
+use crate::router_client::RouterClient;
+use crate::routing::RoutingTable;
+use crate::secrets::SecretStore;
+use crate::stats::Stats;
+use arc_swap::ArcSwap;
+use std::sync::Arc;
+
+#[derive(Clone)]
+pub struct SharedState(pub Arc<AppState>);
+
+/// The portion of state that is rebuilt whenever the config changes.
+pub struct Live {
+    pub cfg: Config,
+    pub registry: Registry,
+    pub routing: RoutingTable,
+    pub router: RouterClient,
+}
+
+impl Live {
+    pub fn build(cfg: Config, secrets: &SecretStore) -> anyhow::Result<Self> {
+        let router = RouterClient::new(&cfg.router)?;
+        let registry = Registry::from_config(&cfg, secrets)?;
+        let routing = RoutingTable::from_config(&cfg);
+        Ok(Self {
+            cfg,
+            registry,
+            routing,
+            router,
+        })
+    }
+}
+
+pub struct AppState {
+    pub live: ArcSwap<Live>,
+    pub stats: Arc<Stats>,
+    pub secrets: SecretStore,
+    pub config_path: String,
+    pub pipeline: crate::pipeline::Pipeline,
+}
+
+impl std::ops::Deref for SharedState {
+    type Target = AppState;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl SharedState {
+    pub fn build(cfg: Config, config_path: String) -> anyhow::Result<Self> {
+        let secrets_path = sibling(&config_path, "secrets.toml");
+        let secrets = SecretStore::load(&secrets_path);
+        let stats = Stats::new(&cfg.stats);
+        let live = Live::build(cfg, &secrets)?;
+        Ok(SharedState(Arc::new(AppState {
+            live: ArcSwap::from_pointee(live),
+            stats,
+            secrets,
+            config_path,
+            pipeline: crate::pipeline::Pipeline::new(),
+        })))
+    }
+
+    /// Current snapshot of the rebuildable state (safe to hold across await points).
+    pub fn live(&self) -> Arc<Live> {
+        self.0.live.load_full()
+    }
+}
+
+impl AppState {
+    /// Replace the config entirely: validate → build → write to disk → swap.
+    /// If any step fails, the active state and file are left unchanged.
+    pub fn reload(&self, new_cfg: Config) -> anyhow::Result<()> {
+        new_cfg.validate()?;
+        let live = Live::build(new_cfg.clone(), &self.secrets)?;
+        new_cfg.save(&self.config_path)?;
+        self.live.store(Arc::new(live));
+        Ok(())
+    }
+
+    /// Rebuild `Live` from the current config without writing to disk
+    /// (e.g. after a secret change — only provider keys changed).
+    pub fn rebuild(&self) -> anyhow::Result<()> {
+        let cfg = self.live.load_full().cfg.clone();
+        let live = Live::build(cfg, &self.secrets)?;
+        self.live.store(Arc::new(live));
+        Ok(())
+    }
+}
+
+/// Path to file `name` next to `path` (in the same directory).
+fn sibling(path: &str, name: &str) -> String {
+    std::path::Path::new(path)
+        .parent()
+        .map(|d| d.join(name))
+        .unwrap_or_else(|| std::path::PathBuf::from(name))
+        .to_string_lossy()
+        .into_owned()
+}