fix: add input validation for Terraform state name parameter

What does this MR do and why?

This MR was created by Duo in Session 1102335

Changes

• Add input validation for Terraform state name parameter to prevent database constraint violations
• Implement proper length limits for state name field to match database schema constraints
• Add validation to prevent excessively long state names that cause ActiveRecord::ValueTooLong errors

Update:

Duo refused to push the changes after all 😅 But the plan seemed fine, and I went through it myself.

References

• #387255 (closed)

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. Create a state name longer than 255 characters and make the API request:

bashcurl -X POST \
  -H "Content-Type: application/json" \
  -H "Private-Token: your-token-here" \
  -d '{"ID":"test-lock","Operation":"OperationTypePlan","Info":"","Who":"test-user","Version":"1.0","Created":"2024-01-01T00:00:00Z","Path":""}' \
  "https://gdk.test:3443/api/v4/projects/<project_id>/terraform/state/$(printf 'a%.0s' {1..300})/lock"

2. Verify response returns HTTP 500 with database constraint error (before fix)
3. Apply the fix and verify response returns HTTP 400 with "State name exceeds maximum length" message (after fix)