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

default.config.yaml

@@ -85,14 +85,14 @@ llm:
   #   strength: low             # LLM strength for summary generation
   # ───────────────────────────────────────────────────────────────────────────
 
-  # ── TIC background event processor ─────────────────────────────────────────
-  # TIC runs periodically to process pending MCP events (email, calendar, WhatsApp)
-  # and decide whether to surface a notification to the user.
+  # ── Event triage (background event processor) ──────────────────────────────
+  # Event triage runs periodically to process pending MCP events (email, calendar,
+  # WhatsApp) and decide whether to surface a notification to the user.
   #
-  # interval_secs  — how often TIC runs (default: 900 = 15 minutes)
-  # batch_size     — max events processed per tick (default: 50)
+  # interval_secs  — how often it runs (default: 900 = 15 minutes)
+  # batch_size     — max events processed per pass (default: 50)
   #
-  # tic:
+  # event_triage:
   #   interval_secs: 900
   #   batch_size: 50
   # ───────────────────────────────────────────────────────────────────────────