rename the TIC system agent to event triage

TIC said nothing about what the agent does, and named the wrong thing: the
tick belongs to the scheduler, which is generic and lives outside it. The
agent's only decision is whether an incoming event deserves an interruption
— it sorts, it never acts — so it is now event-triage, matching the
functional naming of the two memory lints.

- agents/tic/ -> agents/event-triage/, module tic/ -> event_triage/,
  TicManager -> EventTriageManager, TicConfig -> EventTriageConfig
- agent id and chat source: "tic" -> "event-triage"
- config keys: tic.* -> event_triage.*, and the config.yml section tic: ->
  event_triage: (greenfield: previously set values fall back to defaults)
- i18n en/it/fr: Event triage / Triage eventi / Tri des evenements; dropped
  the stale "TIC sessions" mention from the debug-pages description
- docs/system-agents.md, docs/index.md, docs/settings.md, CLAUDE.md, SKALD.md

src/frontend/api/mod.rs

@@ -53,7 +53,7 @@ pub fn router() -> Router<Arc<Skald>> {
         // Custom slash commands (file-based, read-only listing for autocomplete + /help)
         .route("/commands",                     get(commands::list))
         .route("/sessions",                             get(sessions::list_sessions).post(sessions::create))
-        // System agents (TIC, memory lints) — the caller's own run history, plus
+        // System agents (event triage, memory lints) — the caller's own run history, plus
         // the agent list (settings included only for an admin).
         .route("/system-agents",                        get(system_agents::list_agents))
         .route("/system-agents/runs",                   get(system_agents::list_runs))

src/frontend/api/sessions.rs

@@ -593,7 +593,7 @@ fn build_items<'a>(
             let failed = msg.status == "failed";
             match msg.role {
                 chat_history::Role::User => {
-                    // Skip synthetic messages (TIC notifications, etc.) — they are
+                    // Skip synthetic messages (event triage notifications, etc.) — they are
                     // injected as user turns for the LLM but must not appear in the UI.
                     if msg.is_synthetic {
                         continue;

src/frontend/api/system_agents.rs

@@ -1,5 +1,5 @@
 //! System agents — the background agents the instance runs on a user's behalf
-//! (blueprint §13): TIC and the two memory lints.
+//! (blueprint §13): event triage and the two memory lints.
 //!
 //! **This page has two audiences, and the split is the whole design.**
 //!
@@ -88,7 +88,7 @@ pub async fn list_agents(
 
 #[derive(Deserialize)]
 pub struct ListRunsQuery {
-    /// Narrow to one agent (`tic`). Omitted = every system agent.
+    /// Narrow to one agent (`event-triage`). Omitted = every system agent.
     pub agent_id: Option<String>,
     #[serde(default = "default_page")]
     pub page:     i64,