feat(daemon): adopt Weave Node SDK for tracer provisioning

[rgao-coreweave]

Summary

First PR in the stack migrating GenAI span emission from hand-rolled OTLP to the Weave Node SDK. Adds the weave dependency, replaces initTracer's OTLP exporter + NodeTracerProvider with weave.init() + getWeaveTracer(), wraps each event handler in weave.runIsolated() for per-event span isolation, and drops the service.name resource attribute. The existing genaiSpans helpers keep emitting through the Weave provider's tracer; later PRs migrate each span type to the SDK classes.

Companion SDK PR: wandb/weave#7262 (re-export getWeaveTracer).

Test plan

• npm run build
• npm test

[rgao-coreweave]

• refactor(genaiSpans): drop migrated helpers; keep formatting only #79
• feat(daemon): emit chat spans via weave SDK LLM #78
• feat(daemon): emit subagent invoke_agent spans via weave SDK SubAgent #77
• feat(daemon): emit tool spans via weave SDK Tool #76
• feat(daemon): emit turn spans via weave SDK Turn #75
• feat(daemon): wrap claude code sessions in weave SDK Session #74
• feat(daemon): adopt Weave Node SDK for tracer provisioning #73 👈 (View in Graphite)
• main

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