feat(01-11): implement Overview tab with clock display and activity feed
- ClockDisplay: large countdown timer with MM:SS, break/pause overlays,
hand-for-hand badge, urgent pulse in final 10s, next level preview,
chip-up indicator, BB ante support
- BlindInfo: time-to-break countdown, break-ends-in when on break
- ActivityFeed: recent actions with type icons/colors, relative timestamps,
slide-in animation, view-all link
- Overview page: assembles all components in CONTEXT.md priority order
(clock > break > players > balance > financials > activity)
- Extended ClockSnapshot type with bb_ante, game_type, hand_for_hand,
next level info, chip_up_denomination
- Extended FinancialSummary with detailed breakdown fields
- Added Transaction, DealProposal, DealPlayerEntry types
- Added derived properties: bustedPlayers, averageStack, totalChips
- Added transaction WS message handling
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>