refactor: restructure config to support both networks

[silent-cipher]

Overview

This PR restructures the dealbot configuration system to support running checks across multiple Filecoin networks (calibration and mainnet) simultaneously from a single deployment. Previously, each deployment was locked to a single network via the NETWORK env var.

Motivation

• Multi-network support: Enable a single dealbot instance to monitor both calibration and mainnet
• Network isolation: Each network maintains its own wallet, RPC endpoint, scheduling parameters, and SP blocklists
• Operational flexibility: Reduce infrastructure overhead by consolidating deployments
• Backward compatibility: Existing single-network deployments continue to work via legacy env var translation

Changes

Configuration System Refactor

New Structure:

• Replaced monolithic app.config.ts (431 lines) with modular config system:
  • config/types.ts - TypeScript interfaces for all config sections
  • config/env.schema.ts - Joi validation schemas with per-network rules
  • config/loader.ts - Config loading and assembly logic
  • config/env.parsers.ts - Domain-specific env var parsers
  • config/env.helpers.ts - Primitive env var accessors
  • config/constants.ts - Default values and network prefixes

Environment Variables:

• New NETWORKS env var (comma-separated list, e.g., "calibration,mainnet")
• Per-network prefixed vars: <NETWORK>_WALLET_ADDRESS, <NETWORK>_RPC_URL, etc.

Legacy Compatibility:

• config/legacy-env-compat.ts - Automatic translation of old unprefixed vars to new prefixed format
• Existing deployments work without config changes (single-network mode)
• Translation runs before validation, transparent to application code

API Changes

/api/config endpoint:

// Before:
{
  network: "calibration",
  jobs: { dealsPerSpPerHour: 4, ... }
}

// After:
{
  networks: [
    {
      network: "calibration",
      dealsPerSpPerHour: 4,
      retrievalsPerSpPerHour: 2,
      ...
    },
    {
      network: "mainnet",
      dealsPerSpPerHour: 2,
      retrievalsPerSpPerHour: 1,
      ...
    }
  ]
}

[silent-cipher]

closing this in favor of #570