feat(astrolabe): add dynamic MCP server configuration for testing

Replace static post-installation configuration with dynamic test-time
configuration to support testing multiple MCP server deployments.

Changes:
- Remove static MCP server URL and OAuth client setup from post-installation
- Add configure_astrolabe_for_mcp_server fixture (session-scoped)
- Fixture dynamically configures:
  * Nextcloud system config (mcp_server_url, mcp_server_public_url)
  * OAuth client creation via occ oidc:create
  * Client credential storage (astrolabe_client_id, astrolabe_client_secret)
- Update existing OAuth tests to use dynamic configuration
- Add test_astrolabe_multi_server_integration.py with parametrized tests

Benefits:
- Test Astrolabe with mcp-oauth, mcp-keycloak, mcp-multi-user-basic
- Each test configures for its specific MCP server
- No static configuration conflicts between deployments
- Cleaner post-installation (37 lines, down from 85)

Test Results:
- test_astrolabe_configuration_for_different_servers: PASSED (mcp-oauth, mcp-keycloak)
- test_astrolabe_reconfiguration: PASSED

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

tests/server/oauth/test_nc_php_app_oauth.py

@@ -44,14 +44,32 @@ async def nc_admin_http_client(nextcloud_credentials):
 
 
 @pytest.fixture(scope="module")
-async def authorized_nc_session(browser, nextcloud_credentials):
+async def configure_astrolabe_for_tests(configure_astrolabe_for_mcp_server):
+    """Configure Astrolabe to connect to mcp-oauth server before running tests.
+
+    This module-scoped fixture ensures Astrolabe is properly configured
+    for the mcp-oauth server (http://localhost:8001) before any tests run.
+    """
+    logger.info("Configuring Astrolabe for mcp-oauth server...")
+    await configure_astrolabe_for_mcp_server(
+        mcp_server_internal_url="http://mcp-oauth:8001",
+        mcp_server_public_url="http://localhost:8001",
+    )
+    logger.info("✓ Astrolabe configured for mcp-oauth server")
+
+
+@pytest.fixture(scope="module")
+async def authorized_nc_session(
+    browser, nextcloud_credentials, configure_astrolabe_for_tests
+):
     """Module-scoped fixture that logs in and authorizes the NC PHP app once.
 
     This fixture:
-    1. Creates a browser context
-    2. Logs in to Nextcloud
-    3. Authorizes the MCP Server UI app (if not already authorized)
-    4. Returns the page for use in all tests
+    1. Configures Astrolabe for mcp-oauth server (via configure_astrolabe_for_tests)
+    2. Creates a browser context
+    3. Logs in to Nextcloud
+    4. Authorizes the MCP Server UI app (if not already authorized)
+    5. Returns the page for use in all tests
 
     The authorization is done once and reused for all tests in this module.
     """