fix(assets): track fallback warps in stats.notes and set assertion cap in verify-packs

- Track fallback warps in buildSceneLinks with level and destination names, recording to stats.notes in scene.json
- Expose notes and unresolved in WildernessResult.stats and SceneLinks.notes
- Add MAX_EXPECTED_FALLBACK_WARPS assertion (<= 80) and level breakdown logging in verify-packs.ts to prevent silent proliferation of invented staircases

TAG=agy
CONV=2a1934de-30ef-464e-b3f3-fcbcdbbc49f1

scripts/pack-act-assets.ts

@@ -541,6 +541,7 @@ function buildSceneLinks(
   const outEntrances: SceneEntrance[] = []
   const outWarps: SceneWarp[] = []
   const unplaced: { toLevelId: number; reason: string }[] = []
+  const notes: string[] = []
   const placedSeams = new Set<number>()
   const placedWarps = new Set<number>()
 
@@ -751,6 +752,9 @@ function buildSceneLinks(
       unplaced.push({ toLevelId: edge.to, reason: 'no walkable ground for a fallback warp' })
       return
     }
+    const fromName = worldGraph.levels.get(levelId)?.name ?? `level ${String(levelId)}`
+    const toName = worldGraph.levels.get(edge.to)?.name ?? `level ${String(edge.to)}`
+    notes.push(`fallback warp placed for edge ${fromName} -> ${toName}`)
     outWarps.push(makeWarp(
       edge,
       directionTo(edge.to),
@@ -797,7 +801,7 @@ function buildSceneLinks(
     }
   }
 
-  return { entrances: outEntrances, warps: outWarps, waypoints, unplacedEdges: unplaced }
+  return { entrances: outEntrances, warps: outWarps, waypoints, unplacedEdges: unplaced, notes }
 }
 
 const allNames = await archives.listFiles()
@@ -1157,6 +1161,7 @@ async function bakeDs1Variant(
     readonly mazeWarps: readonly MazeWarp[]
     readonly mazeWaypoints?: readonly MazeWaypoint[]
     readonly landmarks?: readonly { readonly id: string; readonly tileX: number; readonly tileY: number }[]
+    readonly notes?: readonly string[] | undefined
   } = { entrances: [], mazeWarps: [] },
 ): Promise<void> {
   const scene: IsoMapScene = buildIsoMapScene(level, libraries, seed)
@@ -1445,6 +1450,10 @@ async function bakeDs1Variant(
       // Edges the world graph has that this copy of the level has nowhere to
       // put. Reported rather than dropped: each one is a hole in the world.
       unplacedEdges: sceneLinks.unplacedEdges,
+      notes: [
+        ...(generatorLinks.notes ?? []),
+        ...(sceneLinks.notes ?? []),
+      ],
     },
   }
   const sceneBytes = new TextEncoder().encode(JSON.stringify(sceneJson))
@@ -1649,6 +1658,7 @@ for (const entry of LEVELS) {
             ...(Array.isArray(result.stats.landmarkEntities)
               ? { landmarks: result.stats.landmarkEntities as readonly { readonly id: string; readonly tileX: number; readonly tileY: number }[] }
               : {}),
+            ...(Array.isArray(result.stats.notes) ? { notes: result.stats.notes } : {}),
           },
         )
       } catch (err) {

scripts/verify-packs.ts

@@ -295,7 +295,10 @@ interface PackedLinks {
     readonly source?: 'tile' | 'room' | 'fallback'
   }[]
   readonly waypoints?: readonly { readonly waypointId: number }[]
-  readonly stats?: { readonly unplacedEdges?: readonly { readonly toLevelId: number; readonly reason: string }[] }
+  readonly stats?: {
+    readonly unplacedEdges?: readonly { readonly toLevelId: number; readonly reason: string }[]
+    readonly notes?: readonly string[]
+  }
 }
 
 const graph = JSON.parse(await readFile(join(packDir, 'world-graph.json'), 'utf8')) as PackedWorldGraph
@@ -385,13 +388,24 @@ for (const key of orphanEdges.slice(0, 20)) {
 }
 check(orphanEdges.length === 0, `world: no graph edge left without an opening (${String(orphanEdges.length)} orphans)`)
 
-// Not an assertion: an approximate staircase is traversable, just not authentic.
-// The number is printed every run so it cannot creep up unnoticed, and it only
-// falls when a level type's DRLG staircase pass gets transcribed.
+// Cap fallback staircases at the known baseline (80 across 15 levels) so invented
+// positions cannot silently proliferate without being accounted for.
+const MAX_EXPECTED_FALLBACK_WARPS = 80
+check(
+  warpSources.fallback <= MAX_EXPECTED_FALLBACK_WARPS,
+  `world: fallback warps (${String(warpSources.fallback)}) within expected threshold (<= ${String(MAX_EXPECTED_FALLBACK_WARPS)})`,
+)
+
 console.log(
   `\n楼梯来源：美术瓦片 ${String(warpSources.tile)}，迷宫楼梯间 ${String(warpSources.room)}，`
   + `兜底 ${String(warpSources.fallback)}（涉及 ${String(approximateLevels.size)} 个关卡）`,
 )
+if (approximateLevels.size > 0) {
+  const breakdown = [...approximateLevels]
+    .map(id => `${String(id)} (${graphLevelName.get(id) ?? 'unknown'})`)
+    .join(', ')
+  console.log(`   兜底关卡列表: ${breakdown}`)
+}
 
 console.log(`\n${String(checks - failures)}/${String(checks)} 项断言通过（逐像素比对了 ${(comparedPixels / 1048576).toFixed(1)} MB 的索引数据）`)
 if (failures > 0) process.exit(1)

src/game/level-links.ts

@@ -180,6 +180,8 @@ export interface SceneLinks {
    * hole in the world, and the verifier reports on this list.
    */
   readonly unplacedEdges: readonly { readonly toLevelId: number; readonly reason: string }[]
+  /** Diagnostic notes and warnings from link resolution (e.g. fallback warps placed). */
+  readonly notes?: readonly string[]
 }
 
 /**

src/game/wilderness.ts

@@ -325,6 +325,8 @@ export interface WildernessResult {
   /** What the generator did, for reporting and tests. */
   readonly stats: Record<string, unknown> & {
     readonly landmarkEntities?: LandmarkEntity[]
+    readonly notes?: string[]
+    readonly unresolved?: string[]
   }
 }