feat: add docs.update to cli and fix schema resolution

[jeremydw]

This PR adds a docs.update to the CLI and fixes the schema resolution bug I introduced with schema.glob

• Add docs.update <docId> <fieldPath> [value] CLI command for surgically updating a single field in a draft doc by its deep key path
• Support inline JSON values, --file, and stdin for providing the value
• Validate against collection schema by default (--no-validate to skip)
• Add resolveFieldAtPath() to reject unknown field paths during validation (e.g. foo.bar on a schema without a foo field)
• Fix import.meta.glob is not a function error in CLI context by loading schemas via viteSsrLoadModule and passing them through a new collectionSchema option on SaveDraftOptions/UpdateDraftOptions
• Add optional collectionSchema to SaveDraftOptions and UpdateDraftOptions to bypass Vite-dependent getCollection() call

fixes #913

[stevenle]

i think we should add some consistency between docs.update, docs.set, and docs.get. if we choose to add --file flag to docs.update, we should update the latter two to do the same. and if docs.update accepts the value as a command line arg, the docs.set should probably do the same.

can you (or ai) take a stab at what all 3 interfaces should look like?