docs: add Arbitrum and Polygon hosted endpoints

[tvinagre]

Tycho is now live on Arbitrum and Polygon. This updates the Hosted Endpoints page to reflect that.

Changes

• Add Arbitrum and Polygon to the Tycho Indexer URL table.
• Add Arbitrum and Polygon to the Tycho Fynd URL table and protocol-systems table.
• Move the "constantly adding new protocols" hint to right after the API Documentation box, before Plans.
• Add uniswap_v4_hooks to the Fynd Unichain protocol-systems row.

Endpoints

Chain	Indexer	Fynd
Arbitrum	tycho-arbitrum-beta.propellerheads.xyz	tycho-fynd-arbitrum.propellerheads.xyz
Polygon	tycho-polygon-beta.propellerheads.xyz	tycho-fynd-polygon.propellerheads.xyz

Verification

Protocol systems verified live against every endpoint via /v1/protocol_systems:

Chain	Protocol systems
Arbitrum (Indexer + Fynd)	uniswap_v2, uniswap_v3, uniswap_v4, pancakeswap_v3
Polygon (Indexer + Fynd)	uniswap_v2, uniswap_v3, uniswap_v4, quickswap_v2

Fynd Arbitrum and Polygon match their respective Indexer endpoints.

🤖 Generated with Claude Code