Three on-chain signals whales don't want you to see — and the last one has only fired twice in Bitcoin's entire history. Number three: Exchange outflows are spiking. Over 94,000 BTC left centralized exchanges in the last 30 days. When coins leave exchanges, they're not being sold — they're being cold-stored. Accumulation 101. Number two: Whale wallets holding 1,000 to 10,000 BTC just hit a 14-mont…