Feature: Add filter for `docker compose logs` (high-volume, currently proxied raw)

Summary

docker compose logs is currently intercepted via rtk proxy but has no output filter, resulting in 0% token savings. This is a high-volume command that would benefit significantly from filtering.

Usage data

From rtk discover on my machine (last 30 days):

• docker compose logs: 606 runs, estimated ~200K+ tokens saveable
• docker-compose logs (legacy syntax): 40 additional runs

Expected behavior

rtk docker compose logs should filter output similarly to rtk docker logs, which currently achieves ~78-83% savings.

Suggested filter behaviors

1. Tail truncation: When --tail=N is specified, only return the last N lines (already done for docker logs)
2. Timestamp normalization: Collapse repeated timestamps into a single header
3. Service prefix deduplication: When multiple services log the same line (e.g., health checks), collapse with a count
4. ANSI stripping: Remove color codes that bloat token count
5. Known noise patterns: Filter out common low-signal lines (e.g., health: starting, repeated keepalive pings)

Related

• rtk fallback: grep -rn... also hits 0% savings on some patterns — the grep parser appears to fall back silently on certain flag combinations (-rn with path args). Worth investigating alongside this.

Environment

• RTK version: $(rtk --version 2>/dev/null)
• Shell: zsh / macOS Darwin 25.2.0