feat: Add Protocol Buffers Well-Known Types transformation support

[requilence]

Summary

This PR adds support for transforming Protocol Buffers Well-Known Types into more readable formats in the gRPC DevTools message viewer.

Motivation

When debugging gRPC services that use Protocol Buffers Well-Known Types (like google.protobuf.Struct, google.protobuf.Value, etc.),
the raw protobuf representation can be difficult to read. For example, a simple struct appears as:

{
  "fieldsMap": [
    ["key1", { "kind": "stringValue", "stringValue": "value1" }],
    ["key2", { "kind": "numberValue", "numberValue": 42 }]
  ]
}

This PR transforms such structures into clean, readable JSON:

  {
    "key1": "value1",
    "key2": 42
  }

Features

New Checkboxes

1. Struct/Value - Transforms Protocol Buffers Well-Known Types:
   - google.protobuf.Struct → Regular JSON objects
   - google.protobuf.Value wrappers → Unwrapped values
   - google.protobuf.ListValue → Regular arrays
   - google.protobuf.Duration → Human-readable format (e.g., "3500ms")
   - google.protobuf.FieldMask → Comma-separated paths
2. Remove List - Removes the List suffix from repeated field names:
   - recordsList → records
   - Only visible when Struct/Value is enabled
   - Only affects arrays, not fields like todoList: "string"

Implementation Details

• Both checkboxes work independently and persist their state
• Transformations apply to both Preview (tree view) and raw JSON modes
• Follows existing patterns for conditional UI elements (like Sticky Scroll)
• Comprehensive test coverage for all transformation cases

Testing

• Added 17 unit tests covering all Well-Known Types transformations
• Tests verify both enabled and disabled states
• Tests ensure List suffix removal is properly conditional

Breaking Changes

None. All changes are additive and opt-in via checkboxes.

Screenshots

Before

After

🤖 Created with help of Claude Code