fuse: Update fuser dependency 0.15.1 → 0.17.0

fuser 0.17 is needed to support multithreaded FUSE sessions: the new
API requires `Filesystem: Send + Sync + 'static`, which forces proper
Arc-based ownership of the filesystem state and makes it possible to
safely hand the implementation to multiple worker threads.

The breaking API changes and how they are addressed:

- `&self` instead of `&mut self` on all trait methods: the only mutable
  state (open file handles) is now protected by a Mutex.
- New newtypes (INodeNo, FileHandle, LockOwner, Generation) and bitflags
  (OpenFlags, FopenFlags) — updated at call sites.
- readdir/read offsets changed from i64 to u64.
- Session::from_fd now takes SessionACL + Config separately.
- Session::run() is no longer public; replaced by spawn().join().
- reply.error() takes fuser::Errno instead of raw i32.

To satisfy the `'static` bound, serve_tree_fuse() now takes
`Arc<FileSystem>` and `Arc<Repository>`. A pre-built flat Vec<InodeData>
(indexed by ino-1) replaces the old HashMap<Ino, InodeRef<'a>>, removing
the lifetime that was incompatible with `'static`. An InodeLookup index
(path→ino for dirs, LeafId→ino for leaves) handles child ino resolution
without raw pointers.

Assisted-by: OpenCode (claude-sonnet-4-6)
Signed-off-by: Colin Walters <walters@verbum.org>

Author: cgwalters

crates/composefs-fuse/Cargo.toml

@@ -13,6 +13,6 @@ version.workspace = true
 [dependencies]
 anyhow = { version = "1.0.98", default-features = false }
 composefs = { workspace = true }
-fuser = { version = "0.15.1", default-features = false, features = ["abi-7-31"] }
+fuser = { version = "0.17.0", default-features = false }
 log = { version = "0.4.8", default-features = false }
 rustix = { version = "1.0.0", default-features = false, features = ["fs", "mount"] }