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

docs/settings.md

@@ -10,7 +10,7 @@ Each setting is saved individually with its own **Save** button (a few, like the
 
 ## Background agents — not here
 
-The settings for the background agents (TIC, the two memory lints) are **not** on this page. Each one is configured on its own tab of the **System agents** page, next to that agent's run history — see [system-agents.md](system-agents.md).
+The settings for the background agents (event triage, the two memory lints) are **not** on this page. Each one is configured on its own tab of the **System agents** page, next to that agent's run history — see [system-agents.md](system-agents.md).
 
 They are still admin-only, and still instance-wide. They simply live where their run log is, because "why did this agent do nothing last night?" is usually answered half by the schedule and half by the log.