feat: pin template repo versions in step-1b files

[kameshsampath]

Problem

Both step-1b-create-repo.md (GitHub) and step-1b-create-project.md (GitLab) clone the template repos at HEAD:

```bash

GitHub

gh repo create "$REPO_PATH" --template https://github.com/Snowflake-Labs/github-coco-agent ...

GitLab

git clone https://gitlab.com/kameshsampath/gitlab-coco-agent "$PROJECT_NAME"
```

If the template repos change structure (renamed workflows, different CI jobs, schema changes), the skill silently breaks — it clones the new broken state with no version check.

Fix

1. Pin the template to a specific tag or commit SHA in the step files:
   ```bash
   TEMPLATE_TAG="v0.1.0"
   git clone --branch "$TEMPLATE_TAG" https://gitlab.com/kameshsampath/gitlab-coco-agent "$PROJECT_NAME"
   ```

2. Add a TEMPLATE_VERSION field to the manifest so users know which template version their project was created from.

3. Add a note to the Jun 16 / v0.1.0 release checklist to bump the template pin.

Impact

Silent breakage when template repos evolve. Affects all new project creation.