Bump to v0.4.0, update README for volume-based storage, fix Linux alloca

- Update README: persistence docs for v0.4.0 volume-based engine
  (checkpoint_interval, sync_mode, compact_threshold, volume_compression)
- Add test verifying volumes/ directory creation and PRAGMA CHECKPOINT
- Fix Linux build: add #include <alloca.h> for non-Windows platforms
- Format JS/TS files with prettier
- Bump all versions to 0.4.0

Author: semihalev

.github/workflows/ci.yml

@@ -12,7 +12,7 @@ concurrency:
   cancel-in-progress: true
 
 env:
-  STOOLAP_ENGINE_REF: v0.3.7
+  STOOLAP_ENGINE_REF: v0.4.0
 
 jobs:
   build:

.github/workflows/publish.yml

@@ -9,7 +9,7 @@ permissions:
   id-token: write
 
 env:
-  STOOLAP_ENGINE_REF: v0.3.7
+  STOOLAP_ENGINE_REF: v0.4.0
 
 jobs:
   build:

README.md

@@ -127,7 +127,7 @@ import { Database, RunResult } from '@stoolap/node';
 
 #### Persistence
 
-File-based databases persist data to disk using WAL (Write-Ahead Logging) and periodic snapshots. Data survives process restarts.
+File-based databases persist data to disk using WAL (Write-Ahead Logging) and an immutable volume-based storage engine. Hot data lives in memory, cold data is sealed into columnar `.vol` files with zone maps, bloom filters, and LZ4 compression. Data survives process restarts.
 
 ```js
 const db = await Database.open('./mydata');
@@ -148,18 +148,18 @@ await db2.close();
 Pass configuration as query parameters in the path:
 
 ```js
-// Maximum durability: fsync on every WAL write
-const db = await Database.open('./mydata?sync=full');
+// Maximum durability: fsync on every write
+const db = await Database.open('./mydata?sync_mode=full');
 
-// High throughput: no fsync, larger buffers
-const db = await Database.open('./mydata?sync=none&wal_buffer_size=131072');
+// High throughput: no fsync, data durable at checkpoint
+const db = await Database.open('./mydata?sync_mode=none');
 
-// Custom snapshot interval with compression
-const db = await Database.open('./mydata?snapshot_interval=60&compression=on');
+// Custom checkpoint interval with compression
+const db = await Database.open('./mydata?checkpoint_interval=60&compression=on');
 
 // Multiple options
 const db = await Database.open(
-  './mydata?sync=full&snapshot_interval=120&keep_snapshots=10&wal_max_size=134217728'
+  './mydata?sync_mode=normal&checkpoint_interval=120&compact_threshold=4'
 );
 ```
 
@@ -169,26 +169,22 @@ Controls the durability vs. performance trade-off:
 
 | Mode | Value | Description |
 |------|-------|-------------|
-| `none` | `sync=none` | No fsync. Fastest, data may be lost on crash |
-| `normal` | `sync=normal` | Fsync on commit batches. Good balance (default) |
-| `full` | `sync=full` | Fsync on every WAL write. Slowest, maximum durability |
+| `none` | `sync_mode=none` | No fsync. Data durable only after checkpoint |
+| `normal` | `sync_mode=normal` | Fsync every 1 second (batched). DDL fsyncs immediately (default) |
+| `full` | `sync_mode=full` | Fsync on every write. Maximum durability |
 
 ##### All Configuration Parameters
 
 | Parameter | Default | Description |
 |-----------|---------|-------------|
-| `sync` | `normal` | Sync mode: `none`, `normal`, or `full` |
-| `snapshot_interval` | `300` | Seconds between automatic snapshots (5 min) |
-| `keep_snapshots` | `5` | Number of snapshot files to retain |
-| `wal_flush_trigger` | `32768` | WAL flush trigger size in bytes (32 KB) |
-| `wal_buffer_size` | `65536` | WAL buffer size in bytes (64 KB) |
-| `wal_max_size` | `67108864` | Max WAL file size before rotation (64 MB) |
-| `commit_batch_size` | `100` | Commits to batch before syncing (normal mode) |
-| `sync_interval_ms` | `10` | Minimum ms between syncs (normal mode) |
+| `sync_mode` | `normal` | Sync mode: `none`, `normal`, or `full` |
+| `checkpoint_interval` | `60` | Seconds between checkpoint cycles (seal + compact + WAL truncate) |
+| `compact_threshold` | `4` | Number of cold volumes before compaction merges them |
+| `checkpoint_on_close` | `on` | Seal all hot rows on clean shutdown for fast startup |
 | `wal_compression` | `on` | LZ4 compression for WAL entries |
-| `snapshot_compression` | `on` | LZ4 compression for snapshots |
-| `compression` | | Set both `wal_compression` and `snapshot_compression` |
-| `compression_threshold` | `64` | Minimum bytes before compressing an entry |
+| `volume_compression` | `on` | LZ4 compression for cold volume files |
+| `compression` | `on` | Shorthand: set both `wal_compression` and `volume_compression` |
+| `keep_snapshots` | `5` | Number of backup snapshot files to retain |
 
 #### Cloning