feat: ATL durations in brackets, offset and GPU hints; screen for-index, glued strings and onlayer

ATL: `ease(1.0) zoom 1.3`, `ease (0.1)xpos 0.5`, `ease(0.1)rotate 5` and `pause(1.5)` take the duration
in brackets; `offset (x, y)` becomes xoffset/yoffset; lines starting with shader, mesh, u_*, blend or
transform_anchor are skipped as GPU hints. thelewdesthouse drops from about 1400 to 111 rejections.
Screens: `for x index k in seq`, `add"x"` without a space, and `onlayer name` after show/call screen
(the layer is ignored, every screen lives in one layer). Transforms named with a capital letter and
declared in another file are resolved by the prescan, and `__("Name") "text"` is a translatable speaker.

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

backend/tests/test_screens.py

@@ -194,3 +194,44 @@ def test_at_picks_a_transform_by_condition_and_atl_commas_split_statements():
     handler = steps[1]["block"]["steps"]
     assert [s["op"] for s in handler] == ["set", "pause"] and handler[1]["t"] == 0.2
     assert steps[1]["events"] == ["selected"] and steps[2]["events"] == ["deselected"]
+
+
+def test_atl_warper_with_duration_in_brackets():
+    data = parse('transform t:\n    easein(1.0) zoom 1.3 ypos 1.0\n    linear(0.5) xpos 0.2\n')
+    steps = data.atl["t"]["steps"] if "t" in data.atl else data.transforms["t"]
+    assert not data.blockers
+    assert [(s["warp"], s["t"]) for s in steps if s["op"] == "move"] == [("easein", 1.0), ("linear", 0.5)]
+
+
+def test_atl_warper_brackets_glued_to_the_property():
+    data = parse('transform t:\n    ease(0.1)rotate 5\n    easein(0.4)xpos 0.3\n')
+    steps = data.atl["t"]["steps"] if "t" in data.atl else data.transforms["t"]
+    assert not data.blockers
+    assert [(s["t"], sorted(s["props"])) for s in steps if s["op"] == "move"] == [(0.1, ["rotate"]), (0.4, ["xpos"])]
+
+
+def test_atl_bracketed_durations_offset_and_gpu_hints():
+    data = parse('transform t:\n    ease (0.1)xpos 0.503\n    linear 0.2 offset (3, 4)\n    pause (0.8)\n'
+                 '    shader "x"\n    u_width 3.0\n    transform_anchor True\n    xpos 1.0\n')
+    steps = data.atl["t"]["steps"] if "t" in data.atl else data.transforms["t"]
+    assert not data.blockers
+    moves = [s for s in steps if s["op"] == "move"]
+    assert [m["t"] for m in moves] == [0.1, 0.2]
+    assert moves[0]["props"] == {"xpos": 0.503} and moves[1]["props"] == {"xoffset": 3, "yoffset": 4}
+    assert any(s["op"] == "pause" and s["t"] == 0.8 for s in steps)
+
+
+def test_screen_for_index_glued_strings_and_onlayer():
+    data = parse('screen s(items):\n    for item index item.id in items:\n        text"[item]"\n    add"cover_0"\n'
+                 'label start:\n    show screen s(items=[1]) onlayer hud\n    call screen s([2]) onlayer overlay\n')
+    audit_ir(data)
+    require_supported_scripts(data)
+    body = data.screens["s"]["body"]
+    assert body[0]["c"] == "for" and body[0]["body"][0]["w"] == "text" and body[1]["w"] == "add"
+
+
+def test_atl_pause_with_brackets():
+    data = parse('transform t:\n    ease(1.0) alpha 0.1\n    pause(1.5)\n    ease(1.0) alpha 0.8\n')
+    steps = data.atl["t"]["steps"] if "t" in data.atl else data.transforms["t"]
+    assert not data.blockers
+    assert [(s["op"], s["t"]) for s in steps] == [("move", 1.0), ("pause", 1.5), ("move", 1.0)]