hermes - 💡(How to fix) Fix time_reconciler: scaffold plugin models and adapter interfaces

Parent: #29631

Goal

Create the initial time_reconciler plugin package scaffold with provider/context interfaces and synthetic fixtures only.

Scope

• Add bundled plugin directory under plugins/time_reconciler/.
• Add plugin.yaml and __init__.py registering CLI/tool entry points only if consistent with existing plugin conventions.
• Define core dataclasses/Pydantic-like models using stdlib/dataclasses if possible:
  • ProjectRef
  • ActivityBlock
  • ContextEvidence
  • MappingProposal
  • ApprovalManifest
  • AppliedAction
• Define provider protocol/interface for time tracker adapters.
• Define context source protocol/interface for optional cross-source evidence.
• Include synthetic fixture data. Do not include real user, client, domain, channel, project ID, or local path data.

Acceptance Criteria

• Plugin imports cleanly.
• Models serialize/deserialize to JSON without secrets.
• Tests use only synthetic data.
• No real personal/client data appears in code, docs, or fixtures.