feat: hexagonal nodes, bezier edges, thought bubbles & token/cost tracking

[Dhwanil25]

Summary

• FlowGraph: Agent nodes are now hexagons; edges use quadratic bezier curves; active agents show live thought bubbles (last ~80 chars of output) with a glassmorphism style; token progress bars appear under nodes as agents generate output
• multiAgentEngine: Per-agent tokensIn, tokensOut, costUsd fields added to MAAgent; totalCostUsd added to MAState; Anthropic SSE message_start/message_delta events are parsed to capture real token counts; TOKEN_PRICES table + estimateCost() function added; token data flows through streamAnthropic → streamLLM → streamWithFailover → executeWorkers
• UniversePage: Header metrics strip showing total token count and estimated cost (~$X.XXX) when agents have run
• TimelinePanel: Added to repo (was missing from previous commits)

Test plan

• Launch a task with an Anthropic key configured — verify token count and cost appear in the header after agents complete
• Verify agent nodes render as hexagons in the Flow view
• Verify edges between nodes are curved (bezier), not straight lines
• Verify thought bubbles appear next to active agents while they are working
• Verify token progress bars appear under agent hexagons
• Verify Timeline panel renders below the canvas
• Check TypeScript compiles cleanly (npx tsc --noEmit)

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