v0.6.0

Changes

Reorganise raw/ and oop/ source trees into domain subdirectories
(boards/, pipelines/, repos/, core/, overview/, settings/) and add
extensive new coverage across both layers:

Raw layer additions:

• core/: process, search
• overview/: dashboard, wiki
• pipelines/: agent pools, environments, secure files, service endpoints
• repos/: branch/tag refs, policies, policy types
• settings/: notifications, service endpoints

OOP layer additions:

• boards/: WorkItemType, ProjectBoards facade
• core/: cross-project Search
• overview/: Dashboard, Wiki
• pipelines/: Agent, Environment, PipelineLibrary, SecureFile,
  ServiceEndpoint, ProjectPipelines facade
• repos/: Branch, Tag, Policy, PolicyTypes, ProjectRepos facade
• settings/: ProjectSettings

Smoke tests replaced with a structured integration test suite under
tests/integration/raw/ and tests/integration/oop/, each module
covering one domain. Unit test coverage kept at 100%.

Exceptions module extracted to src/pyado/exceptions.py.