refactor(cli): batched purge in cmd_purge and cmd_trash_empty (Plan B Phase 6)

Renames purge_item to purge_item_filesystem — body becomes filesystem-only
(remove item.enc, remove attachments/<id>/, manifest.remove). Returns the
relative paths it removed. cmd_purge and cmd_trash_empty accumulate the
paths and fire ONE git rm + ONE git add + ONE git commit per invocation.
A 50-item trash empty now produces 3 git subprocesses regardless of N
(was N+2). New regression test trash_empty_batches_into_one_commit asserts
the one-commit invariant via git rev-list --count.

crates/relicario-cli/src/commands/trash.rs

@@ -39,29 +39,29 @@ pub fn cmd_restore(query: String) -> Result<()> {
     Ok(())
 }
 
-/// Inner purge: assumes vault is already unlocked and manifest is loaded.
-/// Caller is responsible for saving the manifest and committing afterwards.
-pub(super) fn purge_item(
+/// Filesystem-only purge: removes the item.enc, attachments/<id>/, and updates
+/// the manifest in memory. Returns the relative paths the caller must stage
+/// via `git rm` after the loop. Does NOT invoke any git commands — the caller
+/// batches them.
+pub(super) fn purge_item_filesystem(
     vault: &crate::session::UnlockedVault,
     manifest: &mut relicario_core::Manifest,
     id: &relicario_core::ItemId,
     title: &str,
-) -> Result<()> {
+) -> Result<Vec<String>> {
     use std::fs;
 
+    let item_rel = format!("items/{}.enc", id.as_str());
+    let att_rel = format!("attachments/{}", id.as_str());
+
     let item_path = vault.item_path(id);
     if item_path.exists() { fs::remove_file(&item_path)?; }
     let att_dir = vault.root().join("attachments").join(id.as_str());
     if att_dir.exists() { fs::remove_dir_all(&att_dir)?; }
     manifest.remove(id);
 
-    let _ = crate::helpers::git_command(vault.root(), &["rm", "-rf", "--ignore-unmatch",
-        &format!("items/{}.enc", id.as_str()),
-        &format!("attachments/{}", id.as_str()),
-    ]).status()?;
-    // Note: caller adds+commits manifest.enc after processing all purges.
     eprintln!("Purged: {title}");
-    Ok(())
+    Ok(vec![item_rel, att_rel])
 }
 
 pub fn cmd_purge(query: String) -> Result<()> {
@@ -72,11 +72,19 @@ pub fn cmd_purge(query: String) -> Result<()> {
     let title = entry.title.clone();
     let _ = entry;
 
-    purge_item(&vault, &mut manifest, &id, &title)?;
+    let paths = purge_item_filesystem(&vault, &mut manifest, &id, &title)?;
     vault.after_manifest_change(&manifest)?;
 
     let purge_ctx = format!("purge \"{}\" ({})", title, id.as_str());
-    crate::helpers::git_run(vault.root(), &["add", "manifest.enc"], &format!("{purge_ctx}: git add manifest.enc"))?;
+    let mut rm_args: Vec<&str> = vec!["rm", "-rf", "--ignore-unmatch"];
+    let path_refs: Vec<&str> = paths.iter().map(String::as_str).collect();
+    rm_args.extend(path_refs.iter().copied());
+    crate::helpers::git_run(vault.root(), &rm_args, &format!("{purge_ctx}: git rm"))?;
+    crate::helpers::git_run(
+        vault.root(),
+        &["add", "manifest.enc"],
+        &format!("{purge_ctx}: git add manifest.enc"),
+    )?;
     crate::helpers::git_run(
         vault.root(),
         &["commit", "-m", &format!("purge: {} ({})", title, id.as_str())],
@@ -113,13 +121,19 @@ pub fn cmd_trash_empty() -> Result<()> {
         return Ok(());
     }
 
-    let mut purged_titles = Vec::new();
+    let mut all_paths: Vec<String> = Vec::new();
+    let purged_count = purgeable.len();
     for (id, title) in purgeable {
-        purge_item(&vault, &mut manifest, &id, &title)?;
-        purged_titles.push(title);
+        let mut paths = purge_item_filesystem(&vault, &mut manifest, &id, &title)?;
+        all_paths.append(&mut paths);
     }
 
     vault.after_manifest_change(&manifest)?;
+
+    let mut rm_args: Vec<&str> = vec!["rm", "-rf", "--ignore-unmatch"];
+    let path_refs: Vec<&str> = all_paths.iter().map(String::as_str).collect();
+    rm_args.extend(path_refs.iter().copied());
+    crate::helpers::git_run(vault.root(), &rm_args, "trash empty: git rm")?;
     crate::helpers::git_run(
         vault.root(),
         &["add", "manifest.enc"],
@@ -127,10 +141,10 @@ pub fn cmd_trash_empty() -> Result<()> {
     )?;
     crate::helpers::git_run(
         vault.root(),
-        &["commit", "-m", &format!("trash empty: purged {} item(s)", purged_titles.len())],
+        &["commit", "-m", &format!("trash empty: purged {} item(s)", purged_count)],
         "trash empty: git commit",
     )?;
 
-    eprintln!("Emptied trash: {} item(s)", purged_titles.len());
+    eprintln!("Emptied trash: {} item(s)", purged_count);
     Ok(())
 }

crates/relicario-cli/tests/basic_flows.rs

@@ -109,6 +109,72 @@ fn rm_restore_purge_cycle() {
     assert!(!String::from_utf8(out.stdout).unwrap().contains("target"));
 }
 
+#[test]
+fn trash_empty_batches_into_one_commit() {
+    let v = TestVault::init();
+
+    // Add 3 items.
+    for title in ["alpha", "bravo", "charlie"] {
+        let out = v.run(&[
+            "add", "login",
+            "--title", title,
+            "--username", "u",
+            "--password", "p",
+        ]);
+        assert!(out.status.success(), "add {title} failed");
+    }
+
+    // Soft-delete all 3.
+    for title in ["alpha", "bravo", "charlie"] {
+        let out = v.run(&["rm", title]);
+        assert!(out.status.success(), "rm {title} failed");
+    }
+
+    // Set retention to 0 days so the recently-trashed items become purgeable
+    // (should_purge: now - trashed_at > 0 * 86400 = 0).
+    let out = v.run(&["settings", "trash-retention", "--days", "0"]);
+    assert!(out.status.success(), "settings trash-retention failed");
+
+    // Brief sleep to ensure now > trashed_at by at least 1 second
+    // (otherwise should_purge returns false at strict-greater-than equality).
+    std::thread::sleep(std::time::Duration::from_secs(1));
+
+    // Count commits before.
+    let before = std::process::Command::new("git")
+        .args(["rev-list", "--count", "HEAD"])
+        .current_dir(v.path())
+        .output()
+        .unwrap();
+    let before_count: u32 = String::from_utf8(before.stdout).unwrap().trim().parse().unwrap();
+
+    // Run trash empty.
+    let out = v.run(&["trash", "empty"]);
+    assert!(out.status.success(), "trash empty failed: stderr={}",
+            String::from_utf8_lossy(&out.stderr));
+
+    // Count commits after.
+    let after = std::process::Command::new("git")
+        .args(["rev-list", "--count", "HEAD"])
+        .current_dir(v.path())
+        .output()
+        .unwrap();
+    let after_count: u32 = String::from_utf8(after.stdout).unwrap().trim().parse().unwrap();
+
+    assert_eq!(
+        after_count - before_count, 1,
+        "trash empty should fire exactly one commit; before={before_count} after={after_count}"
+    );
+
+    // The remaining `list --trashed` should be empty.
+    let out = v.run(&["list", "--trashed"]);
+    let stdout = String::from_utf8(out.stdout).unwrap();
+    let stderr = String::from_utf8(out.stderr).unwrap();
+    assert!(
+        !stdout.contains("alpha") && !stdout.contains("bravo") && !stdout.contains("charlie"),
+        "items still in trashed list: stdout={stdout} stderr={stderr}"
+    );
+}
+
 #[test]
 fn generate_random_and_bip39() {
     let dir = tempfile::TempDir::new().unwrap();