Milestone 2: persistent blob store, add/materialize/gc

iroh-blobs 0.35 fs store under <store_dir>/blobs. Add imports files or
whole directory trees (as Collections, deterministic order), Materialize
exports them with a real FICLONE reflink attempt and streaming-copy
fallback, Gc is an explicit mark-and-sweep rooted at the pins. Pins,
trusted peers and hash formats persist in meta.json (atomic writes).
Store reads run on a LocalPool because iroh-blobs entry readers are not
Send. Integration tests drive the real daemon binary: directory round
trip byte-identical, gc keeps pinned/drops unpinned, reflink verified on
the repo's own filesystem (XFS), plus a 32-case proptest round trip.

Dependencies: iroh-blobs =0.35.0 (the store itself; pinned per spec),
iroh-io (AsyncSliceReader traits to read store entries), reflink-copy
(FICLONE with copy fallback, per spec), proptest (dev-only, round-trip
property test).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

varde-daemon/src/lib.rs

@@ -5,19 +5,20 @@
 
 pub mod config;
 pub mod daemon;
+pub mod meta;
 pub mod server;
+pub mod store;
 
 use std::sync::Arc;
 
-use anyhow::{Context, Result};
+use anyhow::Result;
 
 /// Run a daemon with the given config until the future is dropped or the
-/// listener fails. Binds the socket before returning control to the
-/// runtime so callers can rely on it existing once this future is polled.
+/// listener fails. The socket is bound before the accept loop starts, so
+/// once this future has been polled the socket path exists.
 pub async fn run(config: config::Config) -> Result<()> {
-    std::fs::create_dir_all(&config.store_dir)
-        .with_context(|| format!("creating store directory {}", config.store_dir.display()))?;
-    let listener = server::bind_socket(&config.socket_path)?;
-    let daemon = Arc::new(daemon::Daemon::new(config));
+    let socket_path = config.socket_path.clone();
+    let daemon = Arc::new(daemon::Daemon::open(config).await?);
+    let listener = server::bind_socket(&socket_path)?;
     server::serve(listener, daemon).await
 }