refactor(cache): redesign cache system with structured keys and improved performance

- Add repo_path parameter to cached_response and cached_vec_response functions
- Implement structured cache key format with namespace, repo_path, and request proto
- Replace global cache with Moka in-memory cache using weight-based eviction
- Set 256MB memory cap with 10-minute TTL and 2-minute TTI policy
- Add metrics collection for cache operations and evictions
- Implement efficient repo-scoped invalidation using key structure
- Add detailed documentation comments explaining cache architecture
- Remove outdated dependencies and update dependency versions
- Add error handling for encoding failures in cache operations
- Optimize Vec responses with length-delimited encoding and pre-allocation

snapshot/sync.rs

@@ -0,0 +1,95 @@
+//! Bundle applicator for restoring snapshots to git repositories.
+//!
+//! Uses `git bundle unbundle` to apply pack data to a bare repository.
+
+use std::path::{Path, PathBuf};
+
+pub struct BundleApplicator {
+    pub repo_path: PathBuf,
+}
+
+impl BundleApplicator {
+    pub fn new(repo_path: PathBuf) -> Self {
+        Self { repo_path }
+    }
+
+    pub fn apply_bundle(&self, data: &[u8]) -> Result<(), String> {
+        let mut child = std::process::Command::new("git")
+            .args([
+                "--git-dir",
+                &self.repo_path.to_string_lossy(),
+                "bundle",
+                "unbundle",
+                "-",
+            ])
+            .stdin(std::process::Stdio::piped())
+            .stdout(std::process::Stdio::piped())
+            .stderr(std::process::Stdio::piped())
+            .spawn()
+            .map_err(|e| format!("spawn git bundle unbundle: {e}"))?;
+        use std::io::Write;
+        if let Some(ref mut stdin) = child.stdin {
+            stdin
+                .write_all(data)
+                .map_err(|e| format!("write bundle: {e}"))?;
+        }
+        let output = child
+            .wait_with_output()
+            .map_err(|e| format!("wait bundle: {e}"))?;
+        if !output.status.success() {
+            return Err(String::from_utf8_lossy(&output.stderr).into_owned());
+        }
+        Ok(())
+    }
+
+    /// Apply bundle from a file path (for streaming writes).
+    pub fn apply_bundle_from_file(&self, path: &Path) -> Result<(), String> {
+        let file = std::fs::File::open(path).map_err(|e| format!("open bundle file: {e}"))?;
+        let mut child = std::process::Command::new("git")
+            .args([
+                "--git-dir",
+                &self.repo_path.to_string_lossy(),
+                "bundle",
+                "unbundle",
+                "-",
+            ])
+            .stdin(std::process::Stdio::piped())
+            .stdout(std::process::Stdio::piped())
+            .stderr(std::process::Stdio::piped())
+            .spawn()
+            .map_err(|e| format!("spawn git bundle unbundle: {e}"))?;
+
+        // Stream file contents to stdin in a background thread
+        let mut stdin = child.stdin.take().ok_or("no stdin")?;
+        let file_handle = file;
+        let writer = std::thread::spawn(move || -> Result<(), String> {
+            use std::io::{Read, Write};
+            let mut reader = std::io::BufReader::new(file_handle);
+            let mut buf = vec![0u8; 65536];
+            loop {
+                match reader.read(&mut buf) {
+                    Ok(0) => break,
+                    Ok(n) => {
+                        stdin
+                            .write_all(&buf[..n])
+                            .map_err(|e| format!("write to stdin: {e}"))?;
+                    }
+                    Err(e) => return Err(format!("read bundle file: {e}")),
+                }
+            }
+            Ok(())
+        });
+
+        let output = child
+            .wait_with_output()
+            .map_err(|e| format!("wait bundle: {e}"))?;
+
+        // Wait for writer thread
+        let _ = writer.join().map_err(|_| "writer thread panicked")?;
+
+        if !output.status.success() {
+            return Err(String::from_utf8_lossy(&output.stderr).into_owned());
+        }
+        Ok(())
+    }
+}