v0.32.5 — separate the Polygon read fallback list from the write RPC

• fix(polymarket) — reads and writes no longer share one RPC list. There was
  a single POLYGON_RPC_URLS, and entry 0 doubled as the sole un-fallbacked
  transport for every SIGNING wallet client (withdraw, redeem, relayer, setup).
  So reordering what read like a read-only fallback list silently changed which
  endpoint broadcasts every money transaction — a write-path change disguised as
  a comment tweak, and one nobody would review as such. 0.32.4 documented the
  hazard; this fixes it. POLYGON_READ_RPC_URLS keeps its fallback() chain;
  POLYGON_WRITE_RPC_URL is a single endpoint, overridable with
  POLYMARKET_WRITE_RPC_URL.

  The write default is publicnode, not 1rpc — 1rpc answers once and then
  returns -32001 "usage limit" (measured 2026-07-21), which is the last thing
  you want broadcasting a withdrawal. And the write side is deliberately a single
  endpoint rather than a fallback chain: viem's fallback() would re-send a
  signed transaction to the next provider on a timeout, and a transaction the
  first provider actually mined must not be broadcast twice. Failing loudly on
  one endpoint is correct; silently retrying a money movement is not.

  Credit to @KillerQueen-Z, who proposed splitting these in #66.

• 211 tests, typecheck, build and verify:prices (28/28) green.