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/mcp-client/src/server.rs

@@ -356,7 +356,7 @@ impl McpServer {
                                 // `notifications/message` is the MCP logging utility
                                 // (deprecated 2026-07-28): route it to the per-server
                                 // log file, not to the notification queue that feeds
-                                // TIC — otherwise log records masquerade as business
+                                // event triage — otherwise log records masquerade as business
                                 // events. Every other notification (e.g. the custom
                                 // `event/*` methods) flows on to `notification_tx`.
                                 if msg.get("method").and_then(Value::as_str) == Some("notifications/message") {