feat(web): technology and runtime marks in the trace waterfall - #2046

🟢 Confidence 10/10 · safe to merge. Resolver and row rendering are pinned by tech.test.ts and the waterfall scene test; the narrow-width kind-label hide rests on preview screenshots.
_{no findings · tests covered · risk medium}

The waterfall now marks what each span called (gen_ai, db, messaging, rpc) and what runs each service (Worker, Effect, or runtime), backed by four more projected span and resource keys. The resolver, the row changes and the Color-by fix added since the last review hold up.

• spanTech picks the called system by gen_ai, db, messaging, then rpc precedence
• serviceMark prefers the Worker mark, then serviceRuntime (Effect, runtime, SDK language)
• spanHierarchyQuery projects 4 more span and 4 more resource attribute keys
• countKeys skips the query's empty "" projections so Color-by offers only real keys

Production impact

_{8f2c591 · Reply "won't fix" to dismiss a finding, or mention @maple-review-bot to ask about one.}