lib.FileContext.chroot: Add property

Give FileContext a read-only property to access self.__chroot, so a caller
holding a context can predict whether the addresses it passes in are
relative to the URI path or absolute.

Signed-off-by: Jan Lindemann <jan@janware.com>
Assisted-by: unsloth/Qwen3.8-27B-GGUF:Q4_K_M with pi.dev v1.0.1

src/python/jw/pkg/lib/FileContext.py

@@ -112,6 +112,10 @@ class FileContext(abc.ABC):
     def root(self) -> str:
         return self.__uri.path
 
+    @property
+    def chroot(self) -> bool:
+        return self.__chroot
+
     @property
     def username(self) -> str | None:
         return self.__uri.username