feat(cua-driver): add aggregate agent session telemetry

[f-trycua]

Summary

• add privacy-bounded start and end events for caller-declared Cua agent sessions
• aggregate duration, tool, action, error, feature-family, and transport usage without exporting session identifiers
• cover in-process CLI, daemon, MCP stdio, and MCP HTTP execution paths
• document the public telemetry contract and inspectable schemas

Validation

• cargo test -p cua-driver-core --locked
• cargo test -p cua-driver --bin cua-driver --locked
• cargo check -p cua-driver-core -p cua-driver --all-targets --locked
• npx tsx scripts/docs-generators/runner.ts --library cua-driver --check
• telemetry inspect for both new event schemas

[github-actions]

📦 Publishable packages changed

• cua-driver-rs

Add release:<service> labels to auto-release on merge (+ optional bump:minor or bump:major, default is patch).
Or add no-release to skip.

cua-driver desktop release validation

Before adding the release label, a maintainer records green runs on the exact release SHA:

• Windows canonical matrix
• macOS logged-in host: scripts/ci/macos/run-rust-e2e.sh, with the typed summary attached to the PR
• Linux X11 canonical matrix
• Linux Sway canonical matrix with environment sway
• Result links and remaining experimental environment gaps are recorded in the PR