feat(integration): Complete feature rewrite with pipeline architecture, effects system, and display improvements

Major changes:
- Pipeline architecture with capability-based dependency resolution
- Effects plugin system with performance monitoring
- Display abstraction with multiple backends (terminal, null, websocket)
- Camera system for viewport scrolling
- Sensor framework for real-time input
- Command-and-control system via ntfy
- WebSocket display backend for browser clients
- Comprehensive test suite and documentation

Issue #48: ADR for preset scripting language included

This commit consolidates 110 individual commits into a single
feature integration that can be reviewed and tested before
further refinement.

tests/conftest.py

@@ -0,0 +1,36 @@
+"""
+Pytest configuration for mainline.
+"""
+
+import pytest
+
+
+def pytest_configure(config):
+    """Configure pytest to skip integration tests by default."""
+    config.addinivalue_line(
+        "markers",
+        "integration: marks tests as integration tests (require external services)",
+    )
+    config.addinivalue_line("markers", "ntfy: marks tests that require ntfy service")
+
+
+def pytest_collection_modifyitems(config, items):
+    """Skip integration/e2e tests unless explicitly requested with -m."""
+    # Get the current marker expression
+    marker_expr = config.getoption("-m", default="")
+
+    # If explicitly running integration or e2e, don't skip them
+    if marker_expr in ("integration", "e2e", "integration or e2e"):
+        return
+
+    # Skip integration tests
+    skip_integration = pytest.mark.skip(reason="need -m integration to run")
+    for item in items:
+        if "integration" in item.keywords:
+            item.add_marker(skip_integration)
+
+    # Skip e2e tests by default (they require browser/display)
+    skip_e2e = pytest.mark.skip(reason="need -m e2e to run")
+    for item in items:
+        if "e2e" in item.keywords and "integration" not in item.keywords:
+            item.add_marker(skip_e2e)