Throwdowns: fixes the docs review found in the kit and its services

- match.teleports lets through only the publishing plugin's own teleports, and only while its
  match runs (its HUD is active, or the native flag is one of its modes); it was merged across
  every plugin and checked no match.
- A mode's timer of 0 or past an hour no longer makes its card do nothing: the native flag takes
  it as 1 to 3600 s. flag.begin's seconds are checked as 1 to 3600, as the flag takes them.
- skater.push and hold(true) return false with a reason without the stock physics, where they
  were dropped unseen.
- telemetry's slam and struck are news since each plugin's own last read; reading them cleared
  them for every plugin.
- A banner or callout of a new match shows whatever serial it starts from, and a document without
  the slot no longer resets its serial.
- SmokeyDawg58's placement no longer divides input.wheel's whole notches by WHEEL_DELTA again.

Extension/Plugins/plugin_runtime.cpp

@@ -73,10 +73,15 @@ public:
         return SkaterState{t.position, heading, t.speed, t.vertical, t.airborne, t.air_time};
     }
     // As the console's tp: refused in a session whose host has turned teleporting (and noclip) off.
-    Teleport teleport(const Vec3& position, float heading) override {
+    Teleport teleport(std::string_view plugin, const Vec3& position, float heading) override {
         // A throwdown mode's own moves (line-ups, recoveries, returns to the start) are the game's:
-        // allowed wherever its match runs and asks for them (the kit's `match.teleports`).
-        if (!session_noclip_allowed() && !throwdowns::kit::match().teleports) return Teleport::forbidden;
+        // allowed while that plugin's own match runs and asks for them (the kit's `match.teleports`),
+        // never for another plugin's calls.
+        if (!session_noclip_allowed()) {
+            const auto flag = throwdowns::kit::flag::state();
+            const bool mine = flag.owned && flag.mode.size() > plugin.size() && flag.mode.starts_with(plugin) && flag.mode[plugin.size()] == '/';
+            if (!throwdowns::kit::allows_teleports(plugin, mine)) return Teleport::forbidden;
+        }
         return teleport_local_skater_heading(position, heading) ? Teleport::sent : Teleport::unavailable;
     }
     std::optional<Vec3> raycast(const Vec3& from, const Vec3& to) override { return local_surface_hit(from, to); }