[EMB-463] Improve developer and agent experience for fdm_materials

[Jelle Spijker (jellespijker)]

EMB-463 Improve Developer and Agent Experience for fdm_materials

This pull request introduces the standardized developer and agent experience improvements for the fdm_materials repository. It establishes clear operational boundaries, pre-commit quality gates, and customized GitHub Copilot rules to streamline both human and AI assistant development while preventing low-level and architecture-level regressions.

Proposed Changes

1. Operational Guidelines (AGENTS.md): Highly tailored developer/agent handbook detailing the specific microservice/library role, dynamic skill discovery (fetching specialized Ultimaker skills), and regional data sovereignty (US/EU separation) rules.
2. Tailored Pre-commit Quality Gate (.pre-commit-config.yaml): Active static quality gates protecting the codebase from leaked credentials, local paths references (/home/jelle/), agent-tracking files (task.md, scratch scripts), and validating bracketed Jira commit ticket prefixes ([EMB-XXXX]).
3. Structured GitHub Copilot Instructions: Personas and strategic directives (PR Assistant, Code Reviewer, Testing Automation, Hardware/Service Integration rules) tailored to this specific repository's tech-stack.

Note

These upgrades are part of a centralized effort to improve developer and autonomous agent safety across the entire 19-repository printer firmware ecosystem.

Warning

Any future repository configuration or behavioral changes should be reflected in AGENTS.md and Copilot instructions to maintain documentation alignment.

Human Review Checklist

• I have verified that the pre-commit config installs and runs cleanly in my local workspace (pre-commit run --all-files).
• I have reviewed the generated AGENTS.md and verified that its technical details and boundaries align with the codebase's architecture and domain context.
• I have reviewed the custom Copilot instructions in .github/copilot-instructions.md and .github/copilot-instructions/.