feat(templates): scaffold a .gitignore that excludes .env and .venv

agentex init writes an .env.example and tells users to create .env with
their API key, and the Dockerfile path is protected by .dockerignore, but no
template ships a .gitignore. A user who git-inits the scaffolded folder
commits .env (and .venv) on the first add. Add a .gitignore to every
template (secrets, Python artifacts, tool caches; .env.example stays
committable) and a test asserting each scaffold renders it.

Claude-Session: https://claude.ai/code/session_01HCVKnA7LeJZ44nxZz1uzF3

Author: michaelxu2288

src/agentex/lib/cli/commands/init.py

@@ -99,6 +99,7 @@ def create_project_structure(
     # Create root files
     root_templates = {
         ".dockerignore.j2": ".dockerignore",
+        ".gitignore.j2": ".gitignore",
         ".env.example.j2": ".env.example",
         "manifest.yaml.j2": "manifest.yaml",
         "README.md.j2": "README.md",

src/agentex/lib/cli/templates/default-claude-code/.gitignore.j2

@@ -0,0 +1,20 @@
+# Secrets and local config
+.env
+.env.*
+!.env.example
+
+# Python
+__pycache__/
+*.py[cod]
+.venv/
+venv/
+*.egg-info/
+build/
+dist/
+
+# Tooling
+.ipynb_checkpoints/
+.pytest_cache/
+.ruff_cache/
+.mypy_cache/
+.DS_Store

src/agentex/lib/cli/templates/default-codex/.gitignore.j2

@@ -0,0 +1,20 @@
+# Secrets and local config
+.env
+.env.*
+!.env.example
+
+# Python
+__pycache__/
+*.py[cod]
+.venv/
+venv/
+*.egg-info/
+build/
+dist/
+
+# Tooling
+.ipynb_checkpoints/
+.pytest_cache/
+.ruff_cache/
+.mypy_cache/
+.DS_Store

src/agentex/lib/cli/templates/default-langgraph/.gitignore.j2

@@ -0,0 +1,20 @@
+# Secrets and local config
+.env
+.env.*
+!.env.example
+
+# Python
+__pycache__/
+*.py[cod]
+.venv/
+venv/
+*.egg-info/
+build/
+dist/
+
+# Tooling
+.ipynb_checkpoints/
+.pytest_cache/
+.ruff_cache/
+.mypy_cache/
+.DS_Store

src/agentex/lib/cli/templates/default-openai-agents/.gitignore.j2

@@ -0,0 +1,20 @@
+# Secrets and local config
+.env
+.env.*
+!.env.example
+
+# Python
+__pycache__/
+*.py[cod]
+.venv/
+venv/
+*.egg-info/
+build/
+dist/
+
+# Tooling
+.ipynb_checkpoints/
+.pytest_cache/
+.ruff_cache/
+.mypy_cache/
+.DS_Store

src/agentex/lib/cli/templates/default-pydantic-ai/.gitignore.j2

@@ -0,0 +1,20 @@
+# Secrets and local config
+.env
+.env.*
+!.env.example
+
+# Python
+__pycache__/
+*.py[cod]
+.venv/
+venv/
+*.egg-info/
+build/
+dist/
+
+# Tooling
+.ipynb_checkpoints/
+.pytest_cache/
+.ruff_cache/
+.mypy_cache/
+.DS_Store

src/agentex/lib/cli/templates/default/.gitignore.j2

@@ -0,0 +1,20 @@
+# Secrets and local config
+.env
+.env.*
+!.env.example
+
+# Python
+__pycache__/
+*.py[cod]
+.venv/
+venv/
+*.egg-info/
+build/
+dist/
+
+# Tooling
+.ipynb_checkpoints/
+.pytest_cache/
+.ruff_cache/
+.mypy_cache/
+.DS_Store

src/agentex/lib/cli/templates/sync-claude-code/.gitignore.j2

@@ -0,0 +1,20 @@
+# Secrets and local config
+.env
+.env.*
+!.env.example
+
+# Python
+__pycache__/
+*.py[cod]
+.venv/
+venv/
+*.egg-info/
+build/
+dist/
+
+# Tooling
+.ipynb_checkpoints/
+.pytest_cache/
+.ruff_cache/
+.mypy_cache/
+.DS_Store

src/agentex/lib/cli/templates/sync-codex/.gitignore.j2

@@ -0,0 +1,20 @@
+# Secrets and local config
+.env
+.env.*
+!.env.example
+
+# Python
+__pycache__/
+*.py[cod]
+.venv/
+venv/
+*.egg-info/
+build/
+dist/
+
+# Tooling
+.ipynb_checkpoints/
+.pytest_cache/
+.ruff_cache/
+.mypy_cache/
+.DS_Store

src/agentex/lib/cli/templates/sync-langgraph/.gitignore.j2

@@ -0,0 +1,20 @@
+# Secrets and local config
+.env
+.env.*
+!.env.example
+
+# Python
+__pycache__/
+*.py[cod]
+.venv/
+venv/
+*.egg-info/
+build/
+dist/
+
+# Tooling
+.ipynb_checkpoints/
+.pytest_cache/
+.ruff_cache/
+.mypy_cache/
+.DS_Store