feat: show key schema and storage details in inspect output

Problem

polkadot-cli inspect lists storage items but doesn't show their key types, hasher algorithms, or modifiers. Users must consult external docs to understand what arguments a storage query expects.

Proposed Solution

Pallet listing level

Show a compact type annotation next to each storage item:

System
  Account         map(AccountId32)
  BlockHash       map(u32)
  Events          value

Detail level

When inspecting a specific storage item, show additional metadata:

System.Account
  Type:     Map
  Key:      AccountId32 (Blake2_128Concat)
  Value:    AccountInfo
  Modifier: Default
  Docs:     The full account information for a particular account ID.

Implementation

Extend StorageItemInfo in src/core/metadata.ts to include:

• Key type names and hasher types
• Value type name
• Modifier (Optional vs Default)

Update src/commands/inspect.ts to render these fields in pretty output. JSON output should include the raw metadata fields.

Priority

MEDIUM

Files

• src/commands/inspect.ts
• src/core/metadata.ts

Start by reading src/core/metadata.ts to understand StorageItemInfo, then trace how src/commands/inspect.ts formats pallet and storage-item output. Done means pretty output shows key types, hashers, value type, modifier, and docs at the requested levels, while JSON output includes the raw metadata fields.