fix(deps): make python-dotenv a base dependency

- the osw CLI is a base console script, but .env loading required osw[mcp]
- without dotenv the implicit .env search returned silently, so the CLI
  reported missing credentials instead of the missing package
- drop the now redundant entry from the mcp extra
- update the docstrings and error message that named osw[mcp]

Author: LukasGold

pyproject.toml

@@ -50,6 +50,9 @@ dependencies = [
     # the osw CLI (src/osw/cli); a base dependency, not an extra, so `pip
     # install osw` never ships a broken `osw` console script
     "typer",
+    # .env loading (osw.service.config). Also a base dependency: without it the
+    # CLI silently cannot find a .env file and reports missing credentials
+    "python-dotenv>=1.0",
 ]
 
 [project.urls]
@@ -76,8 +79,6 @@ mcp = [
     # official MCP Python SDK; provides MCPServer from mcp.server.
     # requires 2.x: 1.x has no MCPServer, and 2.0 removed the vendored FastMCP.
     "mcp>=2",
-    # .env loading for the stdio server (OSW_DOMAIN/OSW_USERNAME/OSW_PASSWORD)
-    "python-dotenv>=1.0",
 ]
 workflow = [
     "prefect>=2.20.25,<3.0",

src/osw/mcp/__init__.py

@@ -5,7 +5,7 @@
 write and manage entities, page slots and files on a live OSL instance.
 
 ``main`` is imported lazily so ``import osw.mcp`` does not require the optional
-``mcp`` / ``python-dotenv`` dependencies unless the server is actually started.
+``mcp`` dependency unless the server is actually started.
 """
 
 from __future__ import annotations

src/osw/service/config.py

@@ -264,7 +264,8 @@ def set_env_file_discovery(enabled: bool) -> None:
 def _load_env_file() -> None:
     """Load a .env file if one is configured or (when enabled) discoverable.
 
-    dotenv is optional (it ships with the ``mcp`` extra). An *explicitly*
+    dotenv is a base dependency, so it is normally present. It is still
+    imported defensively, for an environment that stripped it: an *explicitly*
     configured env file with dotenv missing is an error, because the operator
     asked for something that cannot happen. An implicit search is skipped
     silently.
@@ -286,7 +287,7 @@ def _load_env_file() -> None:
         name = next((n for n in ENV_FILE if os.getenv(n) == path), ENV_FILE[0])
         raise RuntimeError(
             f"{name} is set (to '{path}') but python-dotenv is not installed. "
-            "Install the osw[mcp] extra to use an env file."
+            "Install python-dotenv (a dependency of osw) to use an env file."
         )
     if path:
         dotenv.load_dotenv(path)