Seed cmux Dock panels for the coordinator workspace

[ckrough]

Add a per-repo .cmux/dock.json seeding three Dock panels in this repository's coordinator workspace: a ready-issue watch, gh pr list, and a tail of .daedalus/gates-log.

Dock config is per-repo, so each project commits its own file alongside the repo it serves. This work was tracked in the professional Beads store under prof-blox.6, which covers the daedalus, backchain-plugins, and chiron copies. This repository left the Beads federation on 2026-08-09 (issue #53 removed the .beads/redirect), so its scope splits here, following the precedent set when the internal-plugins scope moved to ckrough/internal-plugins#21.

The ready-issue watch reads GitHub Issues, since .daedalus/config.json binds this repository to "tracker": "github".

Acceptance Criteria

• .cmux/dock.json exists in this repository and defines the three panels.
• Opening this repository's coordinator workspace shows all three panels populated.
• The gates-log panel degrades quietly when .daedalus/gates-log does not exist, rather than erroring.
• The ready-issue panel queries GitHub Issues, not a Beads store.