safe-fs Python: virtual device stat omits uid/gid and fails native os.stat

[kamilio]

With Safe Bash / Safe FS 0.1.684, the custom JSPI Pyodide executor fails native os.stat('/dev/null'):

OSError: [Errno 61] canonical identity or required stat metadata unavailable: '/dev/null'

Reproduced in workerd/Miniflare against an injected authoritative filesystem. Normal native file stat and null descriptor I/O work.

DeviceFileSystem supplies synthetic ino, dev, nlink, size and times for /dev/null and /dev, but omits uid/gid. Python's stat projection requires both and rejects the result. Please provide complete stable virtual-device metadata for path stat/lstat and descriptor fstat, keeping virtual-device identity separate from backing filesystem identity. Add actual native Python tests for os.stat, os.lstat, and os.fstat(os.open('/dev/null', ...)) and /dev metadata.

This is separate from closed #756, which fixed descriptor open/read/write.

[kamilio]

Validated against current main: DeviceFileSystem virtual stat metadata still omits uid/gid. Assigned a dedicated home-owned worktree worker for a focused TDD fix, including path/descriptor metadata and native Python acceptance. Delivery will be direct to main with release monitoring.

[kamilio]

Fix verified on remote main at 6f7e182. Virtual /dev/null and /dev now provide uid/gid without weakening Python validation or merging backing identity. TDD: five metadata regressions and actual Pyodide/workerd errno61 reproduced before fix. GREEN: 157 focused tests, maintained Safe FS typecheck, actual native Python stat/lstat/fstat across all access modes and directory/stability/identity assertions. Parent scoped maintained ESLint policy clean on all changed code/test files. Release publication is monitored separately; no newly published version is claimed yet.