Add charm config for garm configurator

[yhaliaw]

What this PR does

Add charm configs for the garm configurator.
This includes the GitHub creds, and OpenStack creds/configs.

AI Summary

This pull request introduces robust configuration validation and state management to the garm-configurator charm, ensuring that all required OpenStack and GitHub App settings are present and valid before the charm becomes active. It adds a new charm_state.py module to encapsulate configuration logic, updates the charm to use this logic, expands the configuration schema, and adds comprehensive unit tests for all validation scenarios.

Configuration and Validation Improvements:

• Added detailed configuration schema for OpenStack and GitHub App credentials in charmcraft.yaml, including support for Juju secrets for sensitive values.
• Introduced a new charm_state.py module that defines strict validation logic for all configuration options and secrets, raising clear errors when misconfigured.
• Updated the charm's main class (charm.py) to validate configuration on every config change and set the unit's status to Blocked or Active accordingly. [1] [2]

Testing Enhancements:

• Greatly expanded unit tests to cover all validation cases, including missing, empty, or invalid configuration values and secrets, ensuring the charm's status accurately reflects configuration health.

Dependency Updates:

• Added pydantic as a dependency for configuration validation and downgraded ops to version 3.7.0 for compatibility.

Why we need it

Part of the GARM charm feature set.

Checklist

• Changes comply with the project's coding standards and guidelines (see CONTRIBUTING.md and STYLE.md)
• CONTRIBUTING.md has been updated upon changes to the contribution/development process (e.g. changes to the way tests are run)
• Technical author has been assigned to review the PR in case of documentation changes (usually *.md files)
• I updated docs/changelog.md with user-relevant changes
• I used AI to assist with preparing this PR
• I added or updated tests as needed (unit and integration)
• If integration test modules are used: I updated the workflow configuration
  (e.g., in .github/workflows/integration_tests.yaml, ensure the modules list is correct)
• If this PR involves a Grafana dashboard: I added a screenshot of the dashboard
• If this PR involves Terraform: terraform fmt passes and tflint reports no errors
• If this PR involves Rockcraft: I updated the version

[Copilot]

Pull request overview

This PR adds explicit charm configuration schema and validation for the garm-configurator charm, covering required OpenStack settings and GitHub App credentials (including Juju secret-backed values), and wires that validation into unit status reporting.

Changes:

• Adds new charm_state.py module to parse/validate charm config and resolve Juju secrets, raising a structured error on misconfiguration.
• Updates the charm to validate on config-changed and report Active/Blocked via collect-unit-status.
• Expands charm config options in charmcraft.yaml, adds pydantic dependency, and significantly expands unit test coverage for validation cases.

Reviewed changes

Copilot reviewed 7 out of 8 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
docs/changelog.md	Adds a dated entry documenting the new charm configuration support.
charms/garm-configurator/tox.toml	Adds a fmt tox environment for isort + ruff format.
charms/garm-configurator/tests/unit/test_charm.py	Adds extensive validation/status tests for OpenStack + GitHub App config/secrets.
charms/garm-configurator/src/charm.py	Hooks config validation into events and reports unit status.
charms/garm-configurator/src/charm_state.py	Introduces config models + validation and secret resolution logic.
charms/garm-configurator/requirements.txt	Pins ops and adds pydantic.
charms/garm-configurator/charmcraft.yaml	Defines new config options (including secret-typed options).
.gitignore	Ignores .coverage artifact.

[yanksyoon]

Minor comments, thank you!

[florentianayuwono]

lgtm tysm andrew!