[feat]: Added pre-trade risk guardrails with hard order gates

[Official-Krish]

Add a cross-broker Pre-Trade Risk Shield that hard-blocks orders before they are placed, covering Zerodha, Groww, Lighter, and Solana swap nodes.

• Add RiskLimits type + metadata fields (packages/types, node-registry, WorkflowSchema) and persist via workflow create/update routes
• New RiskGuardService: resolves node∩workflow limits (min-wins), computes order notional (live price for Indian symbols), enforces maxQty / maxOrderAmount / maxSlippageBps / maxDailyExposure
• Redis INCRBY daily-exposure ledger keyed by user + date (TTL 48h)
• Hard approval gate (handleBrokerApprovalGate): creates approval, pauses workflow, and throws so the order is never placed
• Non-retryable RiskLimitExceededError; enforcement inserted before executeTrade in base.handler and executeSwap in solana handler
• Close OpenClaw bypass: pre-flight risk check before OpenClaw dispatch
• Best-effort Resend email alerts for blocked / approval-required orders
• Frontend: RiskGuardSection in trading + solana swap forms, RiskBadge on broker nodes, workflow-level risk panel in the save dialog