修复 Studio 失败测试并新增合并门禁

把丢失的 box 录像放回 apps/studio/tests/data/，修掉第 3 节 3–10 号与两处过时测试桩，
注册 timing 标记并让根目录收集零错误；新增 tools/gate.ps1 与可选的 pre-push 钩子。
验证：studio 524 通过 19 跳过、shared 467 通过 18 跳过、ui_check 632 项 0 失败、gate.ps1 退出码 0。
细节见 docs/test-repair-plan.zh.md。

tools/skip_budget.txt

@@ -0,0 +1,22 @@
+# Budgets for tools/gate.ps1. One key per line, `name = integer`; `#` starts a comment.
+#
+#   <suite>_min_tests   the fewest tests the suite may collect. A model that becomes
+#                       uncollectable (a broken import, a renamed module) shrinks the
+#                       suite silently; this floor turns that into a failed gate instead
+#                       of a faster green run.
+#   <suite>_max_skips   the most tests the suite may skip. Skipping is how an environment
+#                       problem or a missing input quietly stops testing anything.
+#
+# Measured on Windows 2026-10-18, after docs/test-repair-plan.zh.md §4 stage 3:
+#   studio  543 collected, 19 skipped (all 19 are "no platform GL context" under the
+#           offscreen plugin; they are the same on every machine without a GL context)
+#   shared  486 collected, 18 skipped   (3 `timing` tests are deselected, not skipped)
+#
+# The ceilings sit a few above today's numbers so a legitimate extra skip does not block
+# work, but a whole module's worth of new skips does. Lower them when skips are fixed;
+# never raise them to make a red gate green.
+
+studio_min_tests = 530
+studio_max_skips = 25
+shared_min_tests = 470
+shared_max_skips = 24