feat(heights): add durable temporary throwable stature

README.md

@@ -41,7 +41,21 @@ Amethyst Shard | Potion of Shifting Stature | Amethyst Shard
 Gold Ingot     | Sugar                      | Gold Ingot
 ```
 
-Produces one Potion of Restoration. Drinking it restores scale to exactly `1.0` (normal size), even outside configured limits. This size is saved across reconnects, respawns, and server restarts. Other saved scales are still clamped to the configured range.
+Produces one Potion of Restoration. Drinking it restores scale to exactly `1.0` (normal size), even outside configured limits. This size is saved across reconnects, respawns, and server restarts. Other permanent saved scales are still clamped to the configured range.
+
+### Temporary splash and lingering variants
+
+Brew any of the four authenticated stature potions with **gunpowder** to make its splash variant; brew that with **dragon's breath** to make its lingering variant. Brewing preserves the stature kind, not arbitrary cosmetic renames/lore. Ordinary potions and cancelled brewing/application events are not overridden. Renaming an ordinary item cannot turn it into a stature potion.
+
+Each splash/cloud applies once per player, without recipient opt-in. The first application saves the player's original base scale. Further applications operate on the temporary scale and reset expiry to **five minutes after the latest application**, including a valid application already at a stature bound. Growth/shrinking respect the current limits; throwable Restoration sets temporary scale to exactly `1.0`.
+
+Example: `1.0 → 0.8`, then `0.8 → 0.6` four minutes later, returns to `1.0` five minutes after the second application. Expiry restores the **exact original baseline**, even if administrator limits changed meanwhile. Offline time counts. Baseline, expiry, and application receipts are persisted; a pending restoration survives disconnect during persistence and is acknowledged only after live application. After that sequence is cleared, ordinary later joins/respawns use the usual limit policy.
+
+Drinking a permanent stature potion ends the temporary sequence, using the current temporary scale (or restored baseline if already expired). Administrator height changes also end the sequence. File writes are serialized off the server tick thread; failed saves do not apply an unsaved change. Disable waits for the active writer and drains its result before returning. Do not forcibly kill the server while it is saving.
+
+Heights tracks only its loaded clouds and checks them every five ticks, dispatching `AreaEffectCloudApplyEvent` and honoring cancellation and recipient filtering. This supports effectless stature clouds without adding a vanilla status effect. Online expiry is checked every second. Durable receipts survive cloud unload and are retired on observed permanent entity removal; abrupt process termination can leave harmless orphan receipts.
+
+**Verification:** automated domain and Bukkit-boundary tests cover this implementation. Actual brewing, cloud delivery, client appearance, and logout/restart gameplay on Purpur 26.2 build 2618 still require manual acceptance checks.
 
 ## Tiny-player launchers
 
@@ -80,13 +94,13 @@ Console is supported. Tab completion suggests subcommands, bound names, and vali
 
 Changes are saved to `plugins/SpigotHeights/config.yml` and take effect without a restart. Minimum must be at least `0.0625`, maximum at most `16.0`, minimum cannot exceed maximum, and the launcher threshold must remain within the range. Invalid changes or save failures leave active settings unchanged.
 
-Players are not immediately resized. Subsequent potion use, joins, and respawns use the new limits; Restoration still returns and preserves exact scale `1.0`. The settings commands only change min/max; edit other settings in the configuration file and restart the server.
+Players are not immediately resized. Subsequent potion use, joins, and respawns use the new limits; Restoration still returns and preserves exact scale `1.0`. Processing an expired temporary sequence is another exception: its exact baseline is restored before ordinary later joins/respawns follow the new limits. The settings commands only change min/max; edit other settings in the configuration file and restart the server.
 
 ### Player height
 
 `/heights player <name>` reports an online player's scale (`1.0` = normal size). If another plugin adds scale modifiers, both the base scale and effective scale are shown.
 
-`/heights player <name> <scale>` immediately sets and saves that player's base scale by UUID. Values must be finite and within current min/max limits, except `1.0` is always allowed. Saved scales follow the usual limits on reconnect and respawn if configuration changes later. A failed save leaves the player's height unchanged.
+`/heights player <name> <scale>` sets that player's base scale by UUID after an asynchronous durable save and ends any temporary sequence. Values must be finite and within current min/max limits, except `1.0` is always allowed. Saved scales follow the usual limits on reconnect and respawn if configuration changes later. A failed save leaves the player's height unchanged.
 
 Player names must match an online player exactly (case-insensitive); partial names and offline players are rejected. Tab completion suggests online names and valid example sizes. Operators, console, and senders with `spigotheights.admin` may view or set heights, including their own.