feat(teams): grant each participant their game's divider role

Reuse the existing CS2/LoL divider roles as participant tags: sync_team_role
now also adds the divider role for the member's team's game, and strips any
other configured divider role (switched game / dropped out). Matched by ID
against config.TEAM_DIVIDERS, so only the divider roles are ever touched.

- TeamSyncResult gains divider_added / divider_removed; summary tallies both
- /teamsync report and log line surface divider_assigned / divider_removed
- tests: grants the game divider, swaps it on a game switch

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XPRsW4tazVtYi2jNzVQkre

strings/member.py

@@ -110,6 +110,8 @@ TEAMSYNC_UI: dict[str, str] = {
     "removed":        "➖ Tiimirolle eemaldatud: {count}",
     "created":        "🆕 Loodud uusi tiimirolle: {roles}",
     "positioned":     "📍 Eraldaja alla paigutatud: {count}",
+    "divider_assigned": "🏷️ Mängurolle (eraldaja) antud: {count}",
+    "divider_removed":  "➖ Mängurolle (eraldaja) eemaldatud: {count}",
     "errors":         "⚠️ Vead: {count}",
     "no_changes":     "✨ Kõik tiimirollid olid juba korras.",
     "changes_header": "**Muudatused:**",