feat: COW always-on architecture + cloud storage clear() fix (v5.11.0)

Major architectural improvements and critical bug fixes:

## COW Always-On Architecture
- Removed cowEnabled flag from BaseStorage (COW cannot be disabled)
- Eliminated marker file system (checkClearMarker, createClearMarker)
- Simplified all code paths to assume COW is always enabled
- COW automatically re-initializes after clear() operations

## Critical Bug Fix: Cloud Storage clear()
- Fixed GCS clear() using correct paths (branches/ instead of entities/nouns/)
- Fixed S3Compatible clear() path structure
- Fixed R2 clear() implementation
- Fixed Azure, FileSystem, OPFS, Memory clear() COW flag handling
- clear() now deletes: branches/, _cow/, _system/
- Result: Cloud buckets can now be fully cleared (previously impossible)

## Container Memory Detection
- Auto-detect Docker/K8s/Cloud Run memory limits (cgroup v1/v2)
- Smart memory allocation (75% graph data, 25% query operations)
- Environment variable support (CLOUD_RUN_MEMORY, MEMORY_LIMIT)
- Production-grade containerized deployment support

## CommitLog streamHistory Feature
- Added streamable commit history with pagination
- Efficient memory usage for large commit histories
- Support for branch filtering and time ranges

## Comprehensive Storage Documentation
- Complete v5.11.0 file structure reference
- Detailed path construction algorithms
- 8 common storage scenarios with examples
- Type-first storage, sharding, COW architecture explained
- Public docs: docs/architecture/data-storage-architecture.md (1063 lines)

## Files Modified (14 files)
- All 8 storage adapters (GCS, S3, R2, Azure, FS, OPFS, Memory, Historical)
- BaseStorage core architecture
- CommitLog with streaming
- Brainy memory configuration
- Parameter validation with container detection
- Storage architecture documentation

## Breaking Changes
NONE - COW was already enabled by default. This removes the ability to disable it.

## Migration
No action required. Upgrade and clear() will work correctly on cloud storage.

## Impact
- Users can now clear cloud storage buckets completely
- No more corrupted buckets after clear() operations
- Container deployments automatically optimize memory allocation
- COW is mandatory and always enabled (safer, simpler)

v5.11.0 - Production ready

src/storage/adapters/opfsStorage.ts

@@ -488,19 +488,11 @@ export class OPFSStorage extends BaseStorage {
         // Delete the entire _cow/ directory (not just contents)
         await this.rootDir!.removeEntry('_cow', { recursive: true })
 
-        // CRITICAL: Reset COW state to prevent automatic reinitialization
-        // When COW data is cleared, we must also clear the COW managers
-        // Otherwise initializeCOW() will auto-recreate initial commit on next operation
+        // v5.11.0: Reset COW managers (but don't disable COW - it's always enabled)
+        // COW will re-initialize automatically on next use
         this.refManager = undefined
         this.blobStorage = undefined
         this.commitLog = undefined
-        this.cowEnabled = false
-
-        // v5.10.4: Create persistent marker file (CRITICAL FIX)
-        // Bug: cowEnabled = false only affects current instance, not future instances
-        // Fix: Create marker file that persists across instance restarts
-        // When new instance calls initializeCOW(), it checks for this marker
-        await this.createClearMarker()
       } catch (error: any) {
         // Ignore if _cow directory doesn't exist (not all instances use COW)
         if (error.name !== 'NotFoundError') {
@@ -528,46 +520,10 @@ export class OPFSStorage extends BaseStorage {
    * @returns true if marker file exists, false otherwise
    * @protected
    */
-  protected async checkClearMarker(): Promise<boolean> {
-    await this.ensureInitialized()
-
-    try {
-      // Get system directory (may not exist yet)
-      const systemDir = await this.rootDir!.getDirectoryHandle('system', { create: false })
-      // Try to get the marker file
-      await systemDir.getFileHandle('cow-disabled', { create: false })
-      return true // Marker exists
-    } catch (error: any) {
-      if (error.name === 'NotFoundError') {
-        return false // Marker doesn't exist (or system dir doesn't exist)
-      }
-      // Other errors (permissions, etc.) - treat as marker not existing
-      console.warn('OPFSStorage.checkClearMarker: Error checking marker', error)
-      return false
-    }
-  }
-
   /**
-   * Create marker indicating COW has been explicitly disabled
-   * v5.10.4: Called by clear() to prevent COW reinitialization on new instances
-   * @protected
+   * v5.11.0: Removed checkClearMarker() and createClearMarker() methods
+   * COW is now always enabled - marker files are no longer used
    */
-  protected async createClearMarker(): Promise<void> {
-    await this.ensureInitialized()
-
-    try {
-      // Get or create system directory
-      const systemDir = await this.rootDir!.getDirectoryHandle('system', { create: true })
-      // Create empty marker file
-      const fileHandle = await systemDir.getFileHandle('cow-disabled', { create: true })
-      const writable = await fileHandle.createWritable()
-      await writable.write(new Uint8Array(0)) // Empty file
-      await writable.close()
-    } catch (error) {
-      console.error('OPFSStorage.createClearMarker: Failed to create marker file', error)
-      // Don't throw - marker creation failure shouldn't break clear()
-    }
-  }
 
   // Quota monitoring configuration (v4.0.0)
   private quotaWarningThreshold = 0.8  // Warn at 80% usage