San Diego FC's supporter community is building its identity through their first MLS season — and each home match writes a chapter you can't go back and be in. Vancouver Whitecaps come to Snapdragon Stadium on May 23 for a Western Conference match with real table stakes. A Pacific Northwest club with decades of MLS history, technically demanding — the kind of opponent that tests whether what's being built here is credible. Snapdragon holds 35,000. The south end supporter section fills first. Get there early enough to be in it when the atmosphere builds. Green Line trolley to Aztec station — the walk from the platform drops you right at …