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

crates/skald-core/src/session/handler/mod.rs

@@ -54,7 +54,7 @@ pub struct PendingMsg {
 /// messages at each round boundary and inject them live into the running turn.
 ///
 /// Passed as `Some` only for the root interactive turn. Sub-agents, resume, and
-/// non-interactive runners (cron, TIC) pass `None` — they never inject.
+/// non-interactive runners (cron, event triage) pass `None` — they never inject.
 #[async_trait]
 pub trait PendingUserInput: Send + Sync {
     /// Drains the leading run of queued non-synthetic user messages, one entry
@@ -256,7 +256,7 @@ pub struct ChatSessionHandler {
     pub(super) source:           String,
     /// True when a real user is actively participating (web, telegram).
     pub(super) is_interactive:   bool,
-    /// True for short-lived automated sessions (cron, tic).
+    /// True for short-lived automated sessions (cron, event-triage).
     pub(super) is_ephemeral:     bool,
     pub(super) tools:            Arc<ToolRegistry>,
     pub(super) mcp:              Arc<dyn McpProvider>,
@@ -270,7 +270,7 @@ pub struct ChatSessionHandler {
     /// Prevents concurrent handle_message calls on the same session.
     pub(super) processing:       Mutex<()>,
     /// When true, any tool call that would require human approval is automatically
-    /// denied instead of blocking. Used by TicManager and other headless runners
+    /// denied instead of blocking. Used by EventTriageManager and other headless runners
     /// that cannot process approval requests.
     pub(super) auto_deny_approvals: Arc<AtomicBool>,
     /// Tool-call ids the user already approved via a resolve endpoint after a restart
@@ -478,7 +478,7 @@ impl ChatSessionHandler {
         system_substitutions:         HashMap<String, String>,
         tx:                           mpsc::Sender<ServerEvent>,
         // True for system-generated messages injected as user turns
-        // (TicManager ticks, notification briefings from ChatHub).
+        // (EventTriageManager passes, notification briefings from ChatHub).
         is_synthetic:                 bool,
         // Structured metadata persisted on the user turn (e.g. file attachments).
         // The projection derives the LLM-facing block; the UI renders chips.