docs: update pylint references to point to requirements-dev.txt

Addresses Copilot review comment — AGENTS.md and skills/dev-workflow/SKILL.md
still referenced requirements.txt for pylint after it was moved to
requirements-dev.txt. Also added pylint to the setup.py dev extra so
`pip install -e ".[dev]"` installs it.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: OMpawar-21

AGENTS.md

@@ -17,7 +17,7 @@
 | Build | `setuptools` / `setup.py`; package `contentstack_management` |
 | HTTP | `requests`, `requests-toolbelt`, `urllib3` |
 | Tests | `pytest` — `tests/integration` (live e2e / sanity, dynamic stack), `tests/unit`, `tests/mock`, `tests/api` (legacy, superseded by `tests/integration`) |
-| Lint / coverage | `pylint`, `coverage` (see `requirements.txt`) |
+| Lint / coverage | `pylint`, `coverage` (see `requirements-dev.txt`) |
 | Secrets / hooks | Talisman, Snyk (see `README.md` development setup) |
 
 ## Source layout

setup.py

@@ -72,7 +72,7 @@ def get_author_email(package):
         "urllib3 >= 2.7.0,<3.0.0",
     ],
     extras_require={
-        "dev": ["pytest>=7.0", "twine>=4.0.2", "packaging>=24.0", "dotenv>=0.0.5"],
+        "dev": ["pytest>=7.0", "twine>=4.0.2", "packaging>=24.0", "dotenv>=0.0.5", "pylint>=2.0.0"],
     },
     python_requires=">=3.9",
 )

skills/dev-workflow/SKILL.md

@@ -19,7 +19,7 @@ description: Use for install, pytest suites, versioning, pylint, hooks, and PR b
 
 ### Before a PR
 
-1. **Install** — `pip install -e ".[dev]"` or install **`requirements.txt`** plus **pytest** / **pytest-cov** as needed.
+1. **Install** — `pip install -e ".[dev]"` then `pip install -r requirements-dev.txt` for linting tools.
 2. **`pytest tests/unit/`** — required baseline (matches CI **`coverage run -m pytest tests/unit/`**).
 3. **API tests** — `pytest tests/api/` when your change affects live CMA behavior; configure **`.env`** per **`tests/cred.py`**. Never commit tokens.
 4. **Mock tests** — `pytest tests/mock/` when extending mocked HTTP or fixtures.
@@ -30,7 +30,7 @@ description: Use for install, pytest suites, versioning, pylint, hooks, and PR b
 
 ### Tooling
 
-- **pylint** is listed in **`requirements.txt`**; follow existing style in touched files.
+- **pylint** is listed in **`requirements-dev.txt`**; follow existing style in touched files.
 - **Husky / Talisman / Snyk** — see **README.md** for local hook setup.
 
 ### Pull requests