test(cli): fix session integration test runner

[Osraka]

Summary

Fixes the account-cli session integration test runner so it uses the local Node process with the workspace-resolved tsx loader instead of invoking npx tsx.

This keeps the test harness aligned with the repo guidance to avoid npx and prevents the session integration tests from timing out when tsx is not available as a workspace dependency.

Details

• Adds tsx as a dev dependency for @base-org/account-cli
• Runs the CLI test fixture with process.execPath --import tsx
• Keeps the production CLI code unchanged

Verification

• corepack yarn workspace @base-org/account-cli test
• corepack yarn workspace @base-org/account-cli typecheck
• corepack yarn workspace @base-org/account-cli build
• corepack yarn exec biome check packages/account-cli/src/commands/session/session.integration.test.ts packages/account-cli/package.json --formatter-enabled=true --linter-enabled=false --organize-imports-enabled=false
• corepack yarn exec biome lint packages/account-cli/src/commands/session/session.integration.test.ts
• git diff --check

Note: the workspace-level account-cli lint / format:check scripts currently fail locally with command not found: biome; the equivalent root yarn exec biome ... checks above pass for the changed files.

[cb-heimdall]

🟡 Heimdall Review Status

Requirement	Status	More Info
Reviews	🟡 0/1	Denominator calculation Show calculation 1 if user is bot 0 1 if user is external 0 2 if repo is sensitive 0 From .codeflow.yml 1 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 1 1 1 if commit is unverified 0 Sum 1