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/index.md

@@ -12,7 +12,7 @@ This index will grow over time. Right now it covers memory, projects, system age
 | --- | --- |
 | [memory.md](memory.md) | Private and shared memory: what goes where, the indexes and history log, why some shared facts can't be changed on request |
 | [projects.md](projects.md) | Projects: shared folders with their own assistant chat, a live file explorer, and member sharing |
-| [system-agents.md](system-agents.md) | Background agents that run on a schedule (TIC, the two memory lints): what they watch, why they only ever report, why a run can be skipped, and their settings |
+| [system-agents.md](system-agents.md) | Background agents that run on a schedule (event triage, the two memory lints): what they watch, why they only ever report, why a run can be skipped, and their settings |
 | [settings.md](settings.md) | The admin's Config page: interface language, the compaction model picker, debug mode |
 
 ## Plugins