P1.2-P1.5: Complete Phase 1 core libraries

Four packages built in parallel:

- P1.2 runtime: Container runtime abstraction with podman implementation.
  Interface (Pull/Run/Stop/Remove/Inspect/List), ContainerSpec/ContainerInfo
  types, CLI arg building, version extraction from image tags. 2 tests.

- P1.3 servicedef: TOML service definition file parsing. Load/Write/LoadAll,
  validation (required fields, unique component names), proto conversion.
  5 tests.

- P1.4 config: CLI and agent config loading from TOML. Duration type for
  time fields, env var overrides (MCP_*/MCP_AGENT_*), required field
  validation, sensible defaults. 7 tests.

- P1.5 auth: MCIAS integration. Token validator with 30s SHA-256 cache,
  gRPC unary interceptor (admin role enforcement, audit logging),
  Login/LoadToken/SaveToken for CLI. 9 tests.

All packages pass build, vet, lint, and test.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

go.sum

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