Refactor session management and resource cleanup

- Replaced `teardownMountedSession` and `flushEditorPackageLoaded` with a unified `SessionLifecycle` approach for managing session transitions and resource cleanup.
- Implemented `SessionLifecycle.endEditorSession` and `SessionLifecycle.endGameSession` to streamline the teardown process for editor and game sessions.
- Introduced `Assets.releaseSession` to handle GPU resource release at session end, ensuring efficient memory management.
- Updated `Game` and `Game2` reset methods to include world and canvas resource releases.
- Enhanced `MapLoader` with a new `releaseAll` method for eager GPU cache cleanup.
- Added tests to verify the new session lifecycle functionality and resource management.

This commit improves the stability and performance of in-process transitions, particularly during editor and game session changes.

further improves and addresses #1662 specifically around android gc pressure.

src/world/MapLoader.lua

@@ -114,12 +114,25 @@ function MapLoader.invalidateAll()
   lru = {}
 end
 
+-- Eagerly release every resident map's TileRenderer GPU objects.  Only safe
+-- when nothing live holds map instances (session end after game:reset).
+function MapLoader.releaseAll()
+  local ids = {}
+  for id in pairs(cache) do ids[#ids + 1] = id end
+  for _, id in ipairs(ids) do MapLoader.evict(id) end
+end
+
 -- kept as the pre-v2 name
 MapLoader.clearCache = MapLoader.invalidateAll
 
 -- the cached Map objects own the per-map TileRenderer instances, so a flush
 -- that skipped this one would leave live SpriteBatches built from the old
--- search path (14 cache-invalidation contract, rows 1 and 3)
-Assets.register(MapLoader.invalidateAll)
+-- search path (14 cache-invalidation contract, rows 1 and 3).  invalidateAll
+-- deliberately does NOT release GPU (hot reload / live overworld); releaseAll
+-- is the session-end path only.
+Assets.register({
+  invalidate = MapLoader.invalidateAll,
+  release = MapLoader.releaseAll,
+})
 
 return MapLoader

src/world/OverworldController.lua

@@ -228,6 +228,11 @@ function OverworldState.computeNeighbors(maps, rootId, hops, reachW, reachH)
   return out
 end
 
+function OverworldState:exit()
+  self.map = nil
+  self.neighbors = nil
+end
+
 function OverworldState:enter(mapId, x, y, facing, opts)
   Game = require("src.core.Game")
   Game.overworld = self

src/world/gen2/World.lua

@@ -5257,6 +5257,37 @@ function World:dropMapImages(mapId)
   if self.connectionMaps then self.connectionMaps[mapId] = nil end
 end
 
+local function safeRelease(obj)
+  if obj and obj ~= false and obj.release then pcall(obj.release, obj) end
+end
+
+-- Eagerly free session-owned GPU caches.  Assets.image-backed atlases are
+-- nilled without release; unique bakes, strips, and roof composites are released.
+function World:release()
+  if self.mapImages then
+    for _, img in pairs(self.mapImages) do safeRelease(img) end
+    self.mapImages = {}
+  end
+  if self.scrollStrips then
+    for _, strip in pairs(self.scrollStrips) do safeRelease(strip) end
+    self.scrollStrips = {}
+  end
+  safeRelease(self.tiltCanvas)
+  self.tiltCanvas = nil
+  if self.grassAtlases then
+    for _, atlas in pairs(self.grassAtlases) do safeRelease(atlas) end
+    self.grassAtlases = {}
+  end
+  if self.atlasCache then
+    for key, atlas in pairs(self.atlasCache) do
+      if key:find("|", 1, true) then safeRelease(atlas) end
+    end
+    self.atlasCache = {}
+  end
+  self.animQuads = nil
+  self.connectionMaps = nil
+end
+
 -- LoadMapAttributes' refill, for every map the session has edited.  Neighbour
 -- strips share the same buffer on the cart, so a connection crossing reloads
 -- them too: this runs on any setMap, seamless or not.