feat(e2e): add local provider support and update test expectations

  Add ability to test migrations with locally built provider binary, and
  update test data to reflect current provider behavior.

  Changes:
  - Add --provider flag to run-e2e-tests script for local provider testing
    - Verifies provider binary exists before running tests
    - Creates .terraformrc-tf-migrate with dev_overrides automatically
    - Applies dev overrides only to v5 tests (v4 uses registry provider)
  - Update zero_trust_gateway_policy migration logic for v5 schema changes
  - Update test expectations for logpull_retention, zero_trust_gateway_policy,
    and zero_trust_list to match current provider output

  The --provider flag enables rapid iteration when fixing provider issues:
    ./scripts/run-e2e-tests --provider /path/to/cloudflare-terraform-next

  This allows testing provider fixes during migration without waiting for
  provider releases, while keeping v4 tests using stable registry versions.

Author: tamas-jozsa

.gitignore

@@ -1,5 +1,8 @@
 tf-migrate
 
+# Local provider dev overrides
+.terraformrc-tf-migrate
+
 # E2E test files
 # Ignore v4 directory except provider.tf and backend.hcl
 e2e/tf/v4/*