Marlens Harvest API V2

Small Ruby client for the Harvest API V2. It uses Ruby's standard library and exposes Marlens::HarvestApiV2::Client#request plus the task-assignment and duration-time-entry calls used by the companion harvest-time-off CLI.

require "marlens/harvest_api_v2"
client = Marlens::HarvestApiV2::Client.from_environment
client.create_time_entry(
  project_id: 48_730_683,
  task_id: 8_083_365,
  spent_date: Date.new(2026, 7, 15),
  hours: 7.5,
  notes: "Vacation"
)

Set HARVEST_ACCESS_TOKEN and HARVEST_ACCOUNT_ID; the client does not read credential files.

Feature and release workflow

Follow docs/workflows/feature-workflow.md: issue and acceptance criteria, issue branch, tested draft PR, reviewed merge to main, version bump, RubyGems publish, remote verification, and isolated install smoke test.