chore(idl): refresh pump.fun IDLs from upstream

Replace idl/pump_fun_idl.json and idl/pump_fees.json with the latest from
pump-fun/pump-public-docs @ 7de0b95 (2026-04-23). pump_swap_idl.json was
already up to date.

Drops the idl/upstream/ vendor copy added in 7864504 in favor of
overwriting in place — the diff lives in git history. README updated to
point at pump-public-docs as the source of truth.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

idl/upstream/SOURCE.md

@@ -1,20 +0,0 @@
-# Upstream pump.fun IDLs
-
-Source: https://github.com/pump-fun/pump-public-docs
-
-Snapshot commit: `7de0b959fa2bdab379a2f75f5433d3de1e35d229` (2026-04-23)
-
-Files:
-- `pump.json` / `pump.ts` — pump.fun bonding curve program
-- `pump_amm.json` / `pump_amm.ts` — pump-swap (PumpAMM) program
-- `pump_fees.json` / `pump_fees.ts` — pump fees program
-
-Kept here verbatim for reference and diffing against the IDLs the bot actually loads from `idl/`. Do not import these directly from runtime code.
-
-To refresh:
-
-```bash
-git clone --depth 1 https://github.com/pump-fun/pump-public-docs.git /tmp/pump-public-docs
-cp /tmp/pump-public-docs/idl/{pump,pump_amm,pump_fees}.{json,ts} idl/upstream/
-# update commit hash above
-```