docs: add Dev Container Template references to all image READMEs

[nozaq]

Summary

Added "Dev Container Template" sections to all image README files, directing users to the corresponding templates in the bare-devcontainer/templates repository. Also enhanced the main README to provide more detailed information about the benefits of using these templates.

Key Changes

• Added a new "Dev Container Template" section to 9 image README files (bun, golang, mise, rust, terraform, uv, zig, debian, and node)
• Each section includes a link to the corresponding template and describes what it provides
• For images with cache directory persistence (bun, golang, mise, rust, terraform, uv, zig), the description mentions "security hardening and volume mounts that persist cache directories for faster rebuilds"
• For simpler images (debian, node), the description mentions "security hardening"
• Updated the main README's "Using a Dev Container Template (Recommended)" section to provide more specific details about what the templates include: security hardening (dropped capabilities, no-new-privileges, non-root user) and cache directory persistence

Implementation Details

• The new sections are consistently placed after the usage/pull command and before the Tags section
• Each template link follows the pattern: https://github.com/bare-devcontainer/templates/tree/main/src/{image-name}
• The main README enhancement clarifies the specific security and performance benefits users can expect from the templates

https://claude.ai/code/session_01RBmRbSubXmgPVedqR727rh