bench 264: dedicated Solana quote-latency (SOL to X)

[Flotapponnier]

New investor-facing bench isolating Solana-origin bridge quote latency, per kyle/12 South Bros request (SOL to Base, Arbitrum, BNB, Ethereum).

• Harness: 3 new quote-only SOL-source routes (SOL->Arb/BNB/Ethereum); SOL->Base already probed. No execution / no funds.
• Recording rules (ocb:bridge_quote_latency_ms_:sol_) scoped to from_chain=Solana, keeping the destination in the chain label so the per-destination tabs work; live on ocb-prom, tracked under infrastructure/monitoring.
• Bench 264 (bridge-quote-latency-solana): providers mobula/relay/lifi/debridge/across/near-intents (Squid/Socket excluded, EVM-only). Live data: SOL->Base p50 mobula 88ms (leads), debridge 173, across 296, relay 494. Arb/BNB/Ethereum fill as the 5min loop probes them.
  Spec validates; harness builds + tests green.