Merge PR #12 and #14 (relay udev retry, catcher crash) into experimental

From curiousjtuber's PRs: the relay leaves a new input node for the next
scan until udev gives it to the input group, rather than marking it seen
after a failed open; and ft-screens' catcher takes a screen's overlays
from one copy of All() instead of begin() and end() of two temporaries,
which crashed libc++ builds on the first click.

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

input/input-relay.py

@@ -1139,6 +1139,11 @@ def main():
                 # New here: a new device, or one that came back in the same place.
                 for old in [n for n in nodes.values() if n.path == path]:
                     drop(old, "replaced by a new device node")
+                # A new node is root's alone until udev gives it to the input group, a moment
+                # after it appears. Opened in that gap, it would fail and never be tried
+                # again: leave it for the next scan instead.
+                if not os.access(path, os.R_OK):
+                    continue
                 seen[path] = ino
                 node = probe(path)
                 if node and node.volume_keys and not take_volume(node):

screens/vr.cpp

@@ -1330,7 +1330,8 @@ void UpdateCatcher() {
     for (int k = 0; k < 3; ++k) params.vSource.v[k] = l.m[k][3], params.vDirection.v[k] = -l.m[k][2];
     for (auto &[i, s] : g_screens) {
         if (!s.visible) continue;
-        std::vector<vr::VROverlayHandle_t> parts(s.All().begin(), s.All().end());
+        const auto all = s.All();  // one copy: two calls give two temporaries, not one range
+        std::vector<vr::VROverlayHandle_t> parts(all.begin(), all.end());
         for (const auto &[k, sub] : s.subs) parts.push_back(sub.overlay);
         for (auto o : parts) {
             vr::VROverlayIntersectionResults_t hit;