feat: add `dot info` command for chain identity and properties

Parent Epic: #63

Summary

Add an info command that shows chain identity information agents need before doing anything on a chain — token symbol, decimals, SS58 prefix, runtime version.

Usage

dot info --output json
dot info --chain kusama --output json

Output

{
  "chain": "polkadot",
  "rpc": "wss://rpc.polkadot.io",
  "tokenSymbol": "DOT",
  "tokenDecimals": 10,
  "ss58Prefix": 0,
  "specName": "polkadot",
  "runtimeVersion": 1003004,
  "palletCount": 68
}

Implementation

• Token symbol/decimals: system_properties RPC call
• SS58 prefix: System.SS58Prefix constant (already queryable)
• Runtime version: state_getRuntimeVersion RPC call or from metadata
• Pallet count: from cached metadata via listPallets()
• Register as new command in cli.ts

Files

• src/commands/info.ts — NEW command
• src/cli.ts — register new command

Verification

• Run dot info --output json on polkadot, kusama, asset hub
• Verify all fields are populated and accurate
• Verify --output pretty produces readable table

Start with the new command described for src/commands/info.ts and the command registration in src/cli.ts. Review the listed system_properties and state_getRuntimeVersion RPC calls, the System.SS58Prefix value, and cached metadata from listPallets(). Run dot info --output json and --output pretty against polkadot, kusama, and asset hub; done means all fields are populated and accurate and the pretty output is readable.