docs: warn that .terraform.lock.hcl corrupts terraform-docs README output

modules/plain-repo/files/CODING_STANDARD.md

@@ -390,6 +390,16 @@ This document defines coding standards for InfraHouse projects.
 * **terraform-docs configuration:**
   - `.terraform-docs.yml` is managed by github-control
   - README.md uses centrally-managed configuration
+* **terraform-docs and `.terraform.lock.hcl` (CRITICAL):**
+  - Never leave `.terraform.lock.hcl` (or `.terraform/`) in the module root when committing
+  - When a lock file is present, terraform-docs writes **resolved** provider versions (e.g. `6.60.0`)
+    into README's Providers table instead of the constraints from `terraform.tf` (e.g. `>= 5.11, < 7.0.0`)
+  - The pre-commit hook regenerates README.md during `git commit` and silently stages the change,
+    so the committed diff can differ from the diff reviewed before committing
+  - If `terraform init` is needed to validate the module, run it in the test root
+    (e.g. `test_data/<module>/`, where init artifacts are gitignored and not read by terraform-docs)
+    instead of the module root, or delete `.terraform/` and `.terraform.lock.hcl` before committing
+  - After committing, verify with `git show --stat` that the commit contains only the intended changes
 
 ### GitHub Pages Documentation (terraform_module)
 * **Deployment:** Automated via `.github/workflows/docs.yml` (managed by github-control)