agent web UI: bulk mark-done for the todos flyout

The per-agent web UI todos flyout (loose-ends v2) had no mark-done
affordance at all — dismissing a todo was only possible via the
cancel_loose_end MCP tool, one id at a time. Add a checkbox per row,
a select-all/select-none/mark-done bulk row, and a new
POST /api/todos/mark-done handler that loops the existing single-id
MarkTodoDone request over the in-agent socket (no new wire request
type needed — the todos list is small, so N same-host round-trips is
cheap).

Fixes #2917

hive-agent/src/web_ui/actions.rs

@@ -1,4 +1,5 @@
-//! Operator action POST handlers (send, cancel, compact, model, effort, reset).
+//! Operator action POST handlers (send, cancel, compact, model, effort,
+//! reset, todos mark-done).
 
 use axum::{
     Form,
@@ -162,3 +163,41 @@ pub(super) async fn post_set_effort(
     tracing::info!(%level, "operator set effort");
     (axum::http::StatusCode::OK, "ok").into_response()
 }
+
+#[derive(Deserialize)]
+pub(super) struct MarkTodosDoneForm {
+    /// Comma-separated todo ids. Same "one field, JS joins the checked
+    /// boxes" shape as `hive-c0re`'s `meta_inputs::MetaUpdateForm` — axum's
+    /// `Form` extractor doesn't natively decode repeated same-name keys.
+    ids: String,
+}
+
+/// `POST /api/todos/mark-done` — dismiss one or more of this agent's own
+/// todos (loose-ends v2) from the todos flyout. Loops a `MarkTodoDone` call
+/// per id over the in-agent socket rather than adding a new bulk request to
+/// `hive-agent-sock`: the todos list is small (single-digit rows most of the
+/// time), so N same-host socket round-trips isn't a real cost, and it keeps
+/// the wire protocol's `Request` enum — already used by the `cancel_loose_end`
+/// MCP tool — unchanged. Unknown/already-acked ids just don't add to the
+/// `acked` count (same "acking twice is not a new action" semantics as the
+/// single-id path); a request with no ids or where every id fails to parse
+/// is rejected as a client error rather than silently acking nothing.
+pub(super) async fn post_mark_todos_done(Form(form): Form<MarkTodosDoneForm>) -> Response {
+    let ids: Vec<i64> = form
+        .ids
+        .split(',')
+        .filter_map(|s| s.trim().parse::<i64>().ok())
+        .collect();
+    if ids.is_empty() {
+        return error_response(StatusCode::BAD_REQUEST, "mark-done: no todo ids selected");
+    }
+    let mut acked = 0u64;
+    for id in ids {
+        if let Some(hive_agent_sock::Response::Acked { count }) =
+            crate::todo_server::dial(&hive_agent_sock::Request::MarkTodoDone { id }).await
+        {
+            acked += count;
+        }
+    }
+    axum::Json(serde_json::json!({ "acked": acked })).into_response()
+}

hive-agent/src/web_ui/mod.rs

@@ -116,6 +116,7 @@ pub async fn serve(
         .route("/api/new-session", post(actions::post_new_session))
         .route("/api/logout", post(auth::post_logout))
         .route("/api/todos", get(stats::api_todos))
+        .route("/api/todos/mark-done", post(actions::post_mark_todos_done))
         .route("/api/stats", get(stats::api_stats))
         .route("/screen/ws", get(screen::screen_ws))
         .route("/icon", get(screen::serve_icon));