fix(8.0): close GA-blocking correctness gaps from the readiness audit

- Version-coupling cold-init: getBrainyVersion() returned a stale build-time
  default ('3.14.0') on the FIRST synchronous call — the one loadPlugins() makes
  to build context.version — because the package.json read was async. A native
  provider declaring a realistic `>=8.0.0` range was therefore rejected on cold
  init. version.ts now reads package.json synchronously (8.0 targets Node-like
  runtimes only); added a cold-init coupling regression with a `^8.0.0` plugin.
- No-silent-failures on the highest-fan-in read path: getNouns()/getVerbs()
  converted a storage read failure into a success-shaped empty page, which the
  cold-start rebuild then read as "store empty" and skipped the rebuild — booting
  a permanently-empty index with no signal (the same silent-failure class as the
  phantom bug). Both now re-throw a named BrainyError; the rebuild path re-throws
  read failures (fail loud) and records a queryable degraded state, surfaced via
  checkHealth(), for non-fatal rebuild hiccups.
- LSM SSTable leak: graph compaction wrote a merged SSTable but only dropped the
  old ones from the manifest, orphaning their payloads forever ("In production
  we'd add a cleanup mechanism"). Added StorageAdapter.deleteMetadata() and now
  reclaim each compacted-away SSTable.
- Documented the two headline methods add() and find() (the only undocumented
  public methods on the class).

Full gate green: build, unit 1512, integration 607.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/storage/baseStorage.ts

@@ -30,6 +30,7 @@ import { getShardId } from './sharding.js'
 import { BlobStorage, type BlobStoreAdapter } from './blobStorage.js'
 import { unwrapBinaryData } from './binaryDataCodec.js'
 import { prodLog } from '../utils/logger.js'
+import { BrainyError } from '../errors/brainyError.js'
 import { MetadataWriteBuffer } from '../utils/metadataWriteBuffer.js'
 import {
   splitNounMetadataRecord,
@@ -1568,23 +1569,24 @@ export abstract class BaseStorage extends BaseStorageAdapter {
         }
       }
 
-      // Storage adapter does not support pagination
-      prodLog.error(
-        'Storage adapter does not support pagination. The deprecated getAllNouns_internal() method has been removed. Please implement getNounsWithPagination() in your storage adapter.'
+      // Storage adapter does not support pagination. This is a hard
+      // misconfiguration — find()/rebuild/aggregation all read through this path,
+      // so returning an empty page would silently present a misconfigured adapter
+      // as an empty database. Fail loud instead.
+      throw BrainyError.storage(
+        'Storage adapter does not implement getNounsWithPagination(). The deprecated getAllNouns_internal() fallback has been removed; implement pagination in your storage adapter.'
       )
-      
-      return {
-        items: [],
-        totalCount: 0,
-        hasMore: false
-      }
     } catch (error) {
-      prodLog.error('Error getting nouns with pagination:', error)
-      return {
-        items: [],
-        totalCount: 0,
-        hasMore: false
-      }
+      // Never convert a genuine read failure into a success-shaped empty page:
+      // this is the highest-fan-in read path (find() fallback, cold-start rebuild
+      // gating, aggregation backfill, getNounsByNounType), so a swallowed error
+      // would propagate as "zero rows" everywhere — indistinguishable from a truly
+      // empty store, and the exact silent-failure class the 8.0 contract forbids.
+      if (error instanceof BrainyError) throw error
+      throw BrainyError.storage(
+        'getNouns pagination read failed',
+        error instanceof Error ? error : undefined
+      )
     }
   }
 
@@ -2415,12 +2417,14 @@ export abstract class BaseStorage extends BaseStorageAdapter {
           : undefined
       }
     } catch (error) {
-      prodLog.error('Error getting verbs with pagination:', error)
-      return {
-        items: [],
-        totalCount: 0,
-        hasMore: false
-      }
+      // Same no-silent-failure contract as getNouns: a genuine read failure must
+      // surface as a named, catchable error, not a success-shaped empty page that
+      // callers read as "this graph has no verbs."
+      if (error instanceof BrainyError) throw error
+      throw BrainyError.storage(
+        'getVerbs pagination read failed',
+        error instanceof Error ? error : undefined
+      )
     }
   }
 
@@ -2576,6 +2580,26 @@ export abstract class BaseStorage extends BaseStorageAdapter {
     return null
   }
 
+  /**
+   * Delete a system/metadata object previously written with {@link saveMetadata}.
+   * The exact inverse of save/get: routes through `analyzeKey(id, 'system')` and
+   * removes the canonical object (plus the legacy flat path that `getMetadata`
+   * also reads, so a sharded key leaves nothing behind). Lets keyed-payload
+   * owners — e.g. the LSM graph store reclaiming its compacted-away SSTables —
+   * free storage instead of orphaning it. Idempotent: deleting a missing path is
+   * a no-op.
+   */
+  public async deleteMetadata(id: string): Promise<void> {
+    await this.ensureInitialized()
+    const keyInfo = this.analyzeKey(id, 'system')
+    await this.deleteCanonicalObject(keyInfo.fullPath)
+    // Mirror getMetadata's legacy fallback so an older flat-path payload for a
+    // sharded key is also reclaimed.
+    if (keyInfo.shardId !== null) {
+      await this.deleteCanonicalObject(`${SYSTEM_DIR}/${id}.json`)
+    }
+  }
+
   /**
    * Save noun metadata to storage (now typed)
    * Routes to correct sharded location based on UUID
@@ -3175,15 +3199,11 @@ export abstract class BaseStorage extends BaseStorageAdapter {
     await this.ensureInitialized()
 
     // Direct O(1) lookup with ID-first paths - no type search needed!
+    // Symmetric with getNounMetadata: readCanonicalObject already returns null for
+    // a genuine not-found, so a real storage fault (permission/corruption/IO) must
+    // propagate rather than be masked as "this verb has no metadata".
     const path = getVerbMetadataPath(id)
-
-    try {
-      const metadata = await this.readCanonicalObject(path)
-      return metadata || null
-    } catch (error) {
-      // Entity not found
-      return null
-    }
+    return this.readCanonicalObject(path)
   }
 
   /**