Document token_address and activity_type filters on activity endpoint

[shaneauerbach]

Summary

• Documents the token_address query param which has been live since Oct 2025 but was never documented
  • Now also supports comma-separated lists: ?token_address=0xA0b8...,0xdAC1...
• Documents the new activity_type query param being added in echo#2369
• Documents the new asset_type query param (native, erc20, erc721, erc1155) being added in echo#2369
• All three filters accept single values or comma-separated lists
• Adds all three params to the OpenAPI spec and a new Filtering section in the mdx

Changes

• evm/openapi/activity.json — added token_address, activity_type, and asset_type query parameters with comma-separated list descriptions
• evm/activity.mdx — replaced Token Filtering section with a Filtering section explaining all server-side filters with examples

Note: the echo PR also extracts ActivityType/AssetType into the shared activity-interpretation crate to eliminate type drift between the activity API and the subscriptions worker.

Closes API-4090

🤖 Generated with Claude Code

[cursor]

PR Summary

Low Risk
Docs/OpenAPI-only updates that expose existing/new query parameters; no runtime or data-handling logic changes in this repo.

Overview
Updates the Activity endpoint docs to replace the generic Token Filtering guidance with a Filtering section that documents server-side query params token_address and activity_type, including allowed activity_type values and a combined example request.

Extends the Activity OpenAPI spec (evm/openapi/activity.json) to formally define these two optional query parameters (including enum validation for activity_type and an example token_address).

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