Test coverage: exclude counterfact-types from Jest and add tests for untested files

[Copilot]

Summary

src/counterfact-types/ is pure TypeScript type declarations — no runtime code, so V8 coverage reported it as 0% and polluted the report. Similarly, src/server/config.ts is a single interface definition. Both are now excluded from coverage collection. Four previously untested modules now have unit tests.

Original Prompt

Exclude the Counterfact-types directory from Jest as it's purely types.

Add tests for any other files that are completely untested.

Manual acceptance tests

• yarn test completes with all suites passing and no failures
• Coverage report no longer lists src/counterfact-types/ or src/server/config.ts entries
• windows-escape.ts shows 100% coverage (was 85%)
• paths-to-routes.ts shows 100% coverage (was 0%)
• telemetry.ts shows ~93% coverage (was 0%); remaining uncovered lines are PostHog network error catch blocks
• read-file.ts shows ~86% coverage (was 0%); remaining uncovered line is the live HTTP fetch branch

Tasks

• jest.config.js — added !src/counterfact-types/** and !src/server/config.ts to collectCoverageFrom
• test/util/windows-escape.test.ts — covers both escapePathForWindows (including the Windows drive-letter branch that was missing) and unescapePathForWindows
• test/util/read-file.test.ts — covers file-path and file:// URL branches via usingTemporaryFiles
• test/cli/telemetry.test.ts — covers all isTelemetryEnabled branches (CI env, explicit opt-in/out, pre-rollout default) and smoke-tests sendTelemetry
• test/migrate/paths-to-routes.test.ts — covers recursive file copy, content rewrite (path-types → types/paths), and missing-source-dir resilience

src/cli/run.ts remains at 0% unit-test coverage; it's the CLI bootstrap that wires together the entire server startup and is covered by the black-box integration tests in test-black-box/.