Fix dependabot updates

[daniel-thom]

A dependabot update got merged accidentally that introduced some clippy errors.

[Copilot]

Pull request overview

Adjusts repo configuration and minor code signatures to resolve clippy issues introduced by an accidental Dependabot merge, and improves dependency/update hygiene going forward.

Changes:

• Adds an explicit where B::Error: Send + Sync + 'static bound to run_app in the TUI to satisfy error trait requirements with anyhow::Result.
• Removes tmux from the Docker runtime package install list to reduce image dependencies.
• Enables weekly Dependabot updates for the Docker ecosystem at the repository root.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/tui.rs	Tightens backend error bounds on run_app to align with anyhow error conversion requirements.
Dockerfile	Drops tmux from installed runtime packages, keeping only required runtime deps.
.github/dependabot.yml	Adds Docker ecosystem updates so base image/Docker deps get automated update PRs.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.