[DEV-70] Improve repository task speed and reliability with Turborepo

[danii1]

Task: DEV-70

Summary: Improve repository task speed and reliability with Turborepo

Implementation Details

Root build, test, lint, typecheck, format, and dev now run through Turborepo so workspace dependencies complete first, independent packages can execute in parallel, and repeatable tasks reuse the local .turbo cache.

• Add Turbo 2.10.11 and a root task graph (turbo.json) with ^build ordering, dist/** / out/** outputs, empty outputs for source-only packages, uncached format, and persistent dev.
• Model the dashboard UI as a Code CLI workspace dependency so Turbo builds it first; keep the package-level bun run build self-contained when Turbo is not driving the graph.
• Ignore .turbo/. Remote caching is not configured.
• Document the root commands, cache invalidation (--force / delete .turbo), and that package-level bun run --filter commands still work.
• CI runs the same Turbo-backed root scripts, with telemetry disabled.

Verification

• Pre-commit format, lint, and typecheck: passed (Turbo cache hits on lint/typecheck).
• Pre-push: all 11 package test suites passed; typecheck passed.