filter(docker): add docker build and docker compose filters

[mpecan]

Goal

Expand Docker filters to cover docker build and docker compose up/logs — the two highest-noise Docker operations. Currently docker/images.toml and docker/ps.toml exist but don't address build or compose output.

Background

docker build (non-BuildKit / --progress=plain): Each RUN step dumps its full stdout/stderr — apt-get installs, pip installs, npm installs. A typical Dockerfile that installs system packages + Python deps + Node deps can emit 1,000+ lines, mostly download progress bars.

docker compose up: Multiplexes logs from all services simultaneously, each prefixed with a color-coded service name. In CI (no TTY) these become plain-text walls with no clear separation between services, making errors from a single service impossible to spot quickly.

Filters to Add

docker/build.toml — docker build / docker buildx build

• Skip: #X [stage/N] RUN ... step headers for successful steps, download/extraction progress lines (Get:, Fetching, Extracting, Pull complete, Digest:, Status:)
• Keep: #X CACHED lines (informational about cache hits), ERROR lines, step headers for the step that failed, COPY / ADD step completion, final Successfully built or error summary
• This is complex because progress format differs between BuildKit and legacy builder

docker/compose.toml — docker compose up / docker compose logs

• Skip: container startup boilerplate (Attaching to ..., Creating network, Pulling lines for successful pulls)
• Keep: Error, error, FATAL, panic, WARN level log lines, port binding confirmations, health check results, lines containing failed / exception / crash
• Note: compose log lines are prefixed with service name; preserve the prefix in kept lines

Fixture Files Needed

• tests/fixtures/docker/build-success.txt — multi-stage build, mostly cached
• tests/fixtures/docker/build-failure.txt — build failure buried in apt-get noise
• tests/fixtures/docker/compose-startup.txt — multi-service compose up output

Acceptance Criteria

• docker/build.toml removes download/extraction progress from successful builds
• Build errors and the failing step context are always preserved
• docker/compose.toml removes routine startup lines
• Error log lines from any service are always preserved
• Integration tests pass for all fixture files