Include .claude/ in Docker images for Haggis agent skills

.claude/ was in .dockerignore, which meant the hyperlane-monorepo Docker image
used as an init container by Haggis never contained the .claude/skills/ directory
or CLAUDE.md. The Claude Agent SDK needs these at runtime (loaded via cwd +
settingSources) for the agent to use domain-specific skills during investigations.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: tkporter

.dockerignore

@@ -17,7 +17,6 @@ rust
 docs
 tools
 vectors
-.claude
 .changeset
 
 # Test & coverage artifacts