Integrate navigator marks into window and grid UI (M8)

Wire the navigator mark API into the window actions, grid badges, and
keyboard/pointer controls:

- Navigator: add a path-based range anchor (p_last_mark) set on `v`
  toggle-on and cleared on unmark-of-anchor / clear_marks / remove /
  mark_removed / rescan-prune; expose navigator_get_last_mark().
  navigator_mark_removed now clears the removed file's mark (decision Q
  / task du0) and the anchor if it was it, without touching unrelated
  marks, and emits "changed" whenever the removed set or marks actually
  changed so grid badges and the header never go stale.
- Window: add win.mark-range (`V`: range from the last-mark anchor to the
  current/grid-selected image), register it, wire Shift+V, and document
  it in the shortcuts overlay. Trash/delete clear marks via mark_removed.
- Grid: middle-click on a cell selects it and dispatches win.mark
  (pointer-accessible marks).
- Tests: unit test_marks_anchor_and_remove and
  test_marks_anchor_pruned_on_rescan; integration test_marks.c covering
  toggle, all+clear, range, persistence across view switch,
  clear-on-trash, and the middle-click gesture wiring; updated
  test_shortcut.c action table + count.

clang-format clean; full suite + ASan leak check green.

1 files changed, 108 insertions, 0 deletions

diff --git a/tests/test_navigator.c b/tests/test_navigator.c
index e8528b1..9cc86f2 100644
--- a/tests/test_navigator.c
+++ b/tests/test_navigator.c
@@ -304,6 +304,110 @@ test_marks(void) {
    cleanup_temp_dir(c_dir);
 }
 
+/* `v` toggle-on records the anchor used by `V` range-mark; unmarking the
+ * anchor drops it. navigator_mark_removed clears the mark (decision Q) and
+ * the anchor if it was the removed file, without touching unrelated marks. */
+static void
+test_marks_anchor_and_remove(void) {
+   char *c_dir = make_temp_dir();
+   write_file(c_dir, "a.jpg", "x", 1);
+   write_file(c_dir, "b.jpg", "x", 1);
+   write_file(c_dir, "c.jpg", "x", 1);
+   GFile *p_a = file_ref(c_dir, "a.jpg");
+   GFile *p_b = file_ref(c_dir, "b.jpg");
+   GFile *p_c = file_ref(c_dir, "c.jpg");
+
+   GFile     *p_dirf = g_file_new_for_path(c_dir);
+   Navigator *p_nav  = navigator_new(p_dirf, GGAZE_SORT_NAME, TRUE, TRUE);
+
+   /* No anchor until a mark is toggled on. */
+   g_assert_null(navigator_get_last_mark(p_nav));
+   navigator_toggle_mark(p_nav, p_a); /* mark a, anchor = a */
+   g_assert_true(g_file_equal(navigator_get_last_mark(p_nav), p_a));
+   g_assert_cmpint(navigator_get_mark_count(p_nav), ==, 1);
+
+   /* Range from anchor a to current c marks a, b, c. */
+   navigator_set_current_file(p_nav, p_c);
+   navigator_mark_range(p_nav, navigator_get_last_mark(p_nav), p_c);
+   g_assert_cmpint(navigator_get_mark_count(p_nav), ==, 3);
+
+   /* Unmarking the anchor drops it; the other marks remain. */
+   navigator_toggle_mark(p_nav, p_a); /* unmark a (was the anchor) */
+   g_assert_null(navigator_get_last_mark(p_nav));
+   g_assert_cmpint(navigator_get_mark_count(p_nav), ==, 2);
+   g_assert_true(navigator_is_marked(p_nav, p_b));
+   g_assert_true(navigator_is_marked(p_nav, p_c));
+
+   /* Re-marking a sets the anchor again; clearing marks drops it. */
+   navigator_toggle_mark(p_nav, p_a); /* mark a, anchor = a */
+   g_assert_true(g_file_equal(navigator_get_last_mark(p_nav), p_a));
+   navigator_clear_marks(p_nav);
+   g_assert_null(navigator_get_last_mark(p_nav));
+   g_assert_cmpint(navigator_get_mark_count(p_nav), ==, 0);
+
+   /* mark_removed clears that file's mark but leaves unrelated marks, and
+    * drops the anchor when the removed file was the anchor. */
+   navigator_toggle_mark(p_nav, p_b); /* mark b, anchor = b */
+   navigator_toggle_mark(p_nav, p_c); /* mark c, anchor = c */
+   g_assert_cmpint(navigator_get_mark_count(p_nav), ==, 2);
+   navigator_mark_removed(p_nav, p_c);
+   g_assert_false(navigator_is_marked(p_nav, p_c));
+   g_assert_true(navigator_is_marked(p_nav, p_b));
+   g_assert_cmpint(navigator_get_mark_count(p_nav), ==, 1);
+   g_assert_null(navigator_get_last_mark(p_nav)); /* anchor was c -> cleared */
+   /* mark_removed on the remaining (non-anchor) mark clears it too. */
+   navigator_mark_removed(p_nav, p_b);
+   g_assert_cmpint(navigator_get_mark_count(p_nav), ==, 0);
+
+   navigator_delete(p_nav);
+   g_object_unref(p_a);
+   g_object_unref(p_b);
+   g_object_unref(p_c);
+   g_object_unref(p_dirf);
+   cleanup_temp_dir(c_dir);
+}
+
+/* The range anchor is dropped when its file leaves the listing via an
+ * external delete + rescan (the monitor path), so `V` no-ops instead of
+ * range-marking from a stale path. */
+static void
+test_marks_anchor_pruned_on_rescan(void) {
+   char *c_dir = make_temp_dir();
+   write_file(c_dir, "a.jpg", "x", 1);
+   write_file(c_dir, "b.jpg", "x", 1);
+   write_file(c_dir, "c.jpg", "x", 1);
+   GFile *p_a = file_ref(c_dir, "a.jpg");
+   GFile *p_b = file_ref(c_dir, "b.jpg");
+   GFile *p_c = file_ref(c_dir, "c.jpg");
+
+   GFile     *p_dirf = g_file_new_for_path(c_dir);
+   Navigator *p_nav  = navigator_new(p_dirf, GGAZE_SORT_NAME, TRUE, TRUE);
+
+   navigator_toggle_mark(p_nav, p_a); /* anchor = a */
+   navigator_toggle_mark(p_nav, p_b);
+   g_assert_cmpint(navigator_get_mark_count(p_nav), ==, 2);
+   g_assert_true(g_file_equal(navigator_get_last_mark(p_nav), p_b));
+
+   /* Externally delete a (the anchor's mark prunes on rescan). */
+   g_assert_true(g_file_delete(p_a, NULL, NULL));
+   navigator_rescan(p_nav);
+   g_assert_cmpint(navigator_get_mark_count(p_nav), ==, 1); /* b remains */
+   g_assert_false(navigator_is_marked(p_nav, p_a));
+
+   /* Externally delete b: the anchor's file is gone, so the anchor drops. */
+   g_assert_true(g_file_delete(p_b, NULL, NULL));
+   navigator_rescan(p_nav);
+   g_assert_cmpint(navigator_get_mark_count(p_nav), ==, 0);
+   g_assert_null(navigator_get_last_mark(p_nav)); /* anchor pruned */
+
+   navigator_delete(p_nav);
+   g_object_unref(p_a);
+   g_object_unref(p_b);
+   g_object_unref(p_c);
+   g_object_unref(p_dirf);
+   cleanup_temp_dir(c_dir);
+}
+
 static void
 test_rescan_and_nearest_fallback(void) {
    char *c_dir = make_temp_dir();
@@ -471,6 +575,10 @@ main(int i_argc, char **c_argv) {
    g_test_add_func("/navigator/prev_next_wrap", test_prev_next_wrap);
    g_test_add_func("/navigator/set_current_file", test_set_current_file);
    g_test_add_func("/navigator/marks", test_marks);
+   g_test_add_func("/navigator/marks_anchor_and_remove",
+                   test_marks_anchor_and_remove);
+   g_test_add_func("/navigator/marks_anchor_pruned_on_rescan",
+                   test_marks_anchor_pruned_on_rescan);
    g_test_add_func("/navigator/rescan_fallback",
                    test_rescan_and_nearest_fallback);
    g_test_add_func("/navigator/remove", test_remove_clears_mark_and_falls_back);