Resolve procedure files from the project root

Every file a procedure references now resolves the same way, locally and on the station, so a procedure in a subfolder of its project behaves the same everywhere.

• Updated local runs, validate and Studio to resolve Python files, sequences, images and panels from the project root (the folder of the nearest pyproject.toml), like a deployed station already did.
• Added a file input type for sequences, and made images and panels written in a sequence file resolve from that file's folder.
• Fixed two Python spellings that passed validate but failed at run time: a file path with no function, and a Windows drive path with a function.
• Added validate warnings for files a deployment will not ship (a Python file or image outside the project, a path under the home folder) and for images that do not exist.