Cleanup deployment workflow and revert chaos changes

[jonathanscholtes]

This pull request removes all Terraform-related steps from the GitHub Actions workflows and updates deployment logic to use static secret values instead of Terraform outputs. Additionally, it simplifies the validation workflow to only run Python linting. There is also a minor bug fix in the API and a configuration improvement for Azure authentication in Terraform providers.

CI/CD Workflow Changes:

• All Terraform steps (init, plan, apply, output reading, and validation) have been removed from the deploy.yml and validate.yml workflows, making deployments rely solely on pre-provisioned infrastructure and static secrets. [1] [2]
• Deployment steps in deploy.yml now use GitHub secrets (such as AZURE_RESOURCE_GROUP, ACR_NAME, CONTAINER_APP_NAME, etc.) directly for resource names and configuration, instead of dynamically reading them from Terraform outputs. [1] [2] [3]
• The validation workflow has been renamed from validate to lint, and now only runs Python linting with ruff on the API codebase. All Terraform format and validation checks have been removed.

Infrastructure as Code Configuration:

• The Terraform provider configuration in infra/providers.tf now explicitly enables OIDC authentication with use_oidc = true for both azurerm and azapi providers, improving security and compatibility with GitHub Actions.

API Bug Fix:

• Fixed a bug in build_line_item_summary in orders.py to use the correct key unit_price instead of price when calculating line item totals.