Add worktrees, per-hunk review, effort per message, regenerate, voice input

- Isolated git worktree per session (create, status, merge, discard)
- Permission card: accept file-edit hunks individually; agent learns what was rejected
- Reasoning effort per message; regenerate the last answer with another model/effort
- Voice input via the Web Speech API
- Folder-up button in the file browser; ssh, rsync and mc in the image

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

server/src/tools/fs.rs

@@ -22,6 +22,27 @@ fn image_type(path: &Path) -> Option<&'static str> {
     }
 }
 
+/// Apply only the selected hunks (indices of the 3-line-context groups, as in
+/// `unified_diff`) of the change old -> new. Returns (result, total hunks).
+pub fn apply_hunks(old: &str, new: &str, selected: &[usize]) -> (String, usize) {
+    let diff = similar::TextDiff::from_lines(old, new);
+    let groups = diff.grouped_ops(3);
+    let total = groups.len();
+    let mut out = String::new();
+    for op in diff.ops() {
+        let in_selected = op.tag() != similar::DiffTag::Equal && groups.iter().enumerate().any(|(i, g)| selected.contains(&i) && g.contains(op));
+        let lines: Vec<&str> = if in_selected {
+            diff.new_slices()[op.new_range()].to_vec()
+        } else {
+            diff.old_slices()[op.old_range()].to_vec()
+        };
+        for l in lines {
+            out.push_str(l);
+        }
+    }
+    (out, total)
+}
+
 pub fn unified_diff(path: &str, old: &str, new: &str) -> String {
     similar::TextDiff::from_lines(old, new)
         .unified_diff()
@@ -235,7 +256,7 @@ impl Tool for Edit {
     }
 }
 
-fn apply_edit(old: &str, input: &Value) -> Result<String> {
+pub fn apply_edit(old: &str, input: &Value) -> Result<String> {
     let from = arg_str(input, "old_string")?;
     let to = arg_str(input, "new_string")?;
     if from.is_empty() {
@@ -484,3 +505,19 @@ mod tests {
         assert!(apply_edit("xyz", &input).is_err());
     }
 }
+
+#[cfg(test)]
+mod hunk_tests {
+    #[test]
+    fn partial_apply() {
+        let old: String = (1..=30).map(|i| format!("line {i}\n")).collect();
+        let new = old.replace("line 2\n", "line TWO\n").replace("line 25\n", "line 25\nextra\n");
+        let (only_first, total) = super::apply_hunks(&old, &new, &[0]);
+        assert_eq!(total, 2);
+        assert!(only_first.contains("line TWO") && !only_first.contains("extra"));
+        let (only_second, _) = super::apply_hunks(&old, &new, &[1]);
+        assert!(!only_second.contains("line TWO") && only_second.contains("extra"));
+        assert_eq!(super::apply_hunks(&old, &new, &[0, 1]).0, new);
+        assert_eq!(super::apply_hunks(&old, &new, &[]).0, old);
+    }
+}