feat: auto-wire telemetry in initSquadTelemetry() (#281)

[bradygaster]

What

initSquadTelemetry() now auto-creates EventBus and CostTracker so users just call:

const telemetry = initSquadTelemetry();
// That's it. Everything lights up.
console.log(telemetry.costTracker.formatSummary());

Changes

• Auto-create EventBus internally if none is provided
• Auto-wire CostTracker to the internal EventBus
• SquadClient.sendMessage() now calls recordTokenUsage() (not just span attributes)
• New SquadClient.sendAndWait() with OTel tracing + metric recording
• Auto-forward session usage events to the EventBus when sessions are created via SquadClient
• Model pricing table included in SDK — users don't maintain their own pricing
• estimateCost() helper for token-based cost estimation
• Expose costTracker and eventBus on SquadTelemetryHandle
• SquadClient accepts optional eventBus parameter for auto-wiring
• New subpath exports: ./runtime/otel-init, ./config/models

Tests

16 new tests covering auto-wiring, pricing, cost accumulation, and unwiring. All 107 related tests pass.

Files Changed

File	Change
packages/squad-sdk/src/runtime/otel-init.ts	Auto-create EventBus + CostTracker, expose on handle
packages/squad-sdk/src/config/models.ts	Add ModelPricing, pricing data, estimateCost()
packages/squad-sdk/src/adapter/client.ts	eventBus option, recordTokenUsage(), sendAndWait(), usage forwarding
packages/squad-sdk/package.json	New subpath exports
test/telemetry-auto-wiring.test.ts	16 new tests

Closes #281

Credit: Brady Gaster (issue author), Squad IRL samples (discovery source)
Working as EECOM (Core Dev)