chore(8.0): modernize toolchain + position Bun as a runtime

Consumer-invisible modernization pass — no public API or runtime-behavior
change; dist for the override-only files is byte-identical.

Toolchain:
- CI: GitHub Actions matrix — Node 22/24 (test:unit) + Bun latest (test:bun).
- engines: node ">=22" (was "22.x"), bun ">=1.1.0".
- tsconfig: isolatedModules + noImplicitOverride; add the 33 `override`
  modifiers the flag requires across storage/integrations/vfs/transaction.
- deps: @types/node ^22; add prettier; drop dead standard-version,
  @rollup/plugin-* and the redundant embedded eslintConfig (flat
  eslint.config.js is the active config — verified identical lint output).

paramValidation: replace the top-level `await import('node:os'/'node:fs')`
with static ESM imports. The top-level-await form poisoned the module graph;
static imports also drop the browser/edge fallback branches no supported
runtime reaches (8.0 is Node/Bun/Deno-only).

Bun positioning: recommend Bun as a runtime (`bun add` / `bun run`), which is
green (test:bun 8/8). Drop single-binary `bun build --compile` as a target —
native addons cannot embed into it, and Bun 1.3.10 has a `--compile` codegen
regression around top-level await. Rename the Bun test to bun-runtime-test.ts
and correct docs that overclaimed single-binary support.

Gates: typecheck 0, build 0, test:unit 1743/1743, test:bun 8/8.

src/storage/adapters/fileSystemStorage.ts

@@ -164,7 +164,7 @@ export class FileSystemStorage extends BaseStorage {
    *
    * @returns FileSystem-optimized batch configuration
    */
-  public getBatchConfig(): StorageBatchConfig {
+  public override getBatchConfig(): StorageBatchConfig {
     return {
       maxBatchSize: 500,
       batchDelayMs: 0,
@@ -180,7 +180,7 @@ export class FileSystemStorage extends BaseStorage {
   /**
    * Initialize the storage adapter
    */
-  public async init(): Promise<void> {
+  public override async init(): Promise<void> {
     if (this.isInitialized) {
       return
     }
@@ -952,7 +952,7 @@ export class FileSystemStorage extends BaseStorage {
    *
    * @param prefix - Storage-root-relative directory prefix to remove.
    */
-  public async removeRawPrefix(prefix: string): Promise<void> {
+  public override async removeRawPrefix(prefix: string): Promise<void> {
     await this.ensureInitialized()
     await fs.promises.rm(path.join(this.rootDir, prefix), { recursive: true, force: true })
   }
@@ -966,7 +966,7 @@ export class FileSystemStorage extends BaseStorage {
    *
    * @param paths - Storage-root-relative object paths previously written.
    */
-  public async syncRawObjects(paths: string[]): Promise<void> {
+  public override async syncRawObjects(paths: string[]): Promise<void> {
     await this.ensureInitialized()
     const parentDirs = new Set<string>()
 
@@ -1539,7 +1539,7 @@ export class FileSystemStorage extends BaseStorage {
   // Removed 10 *_internal method overrides - now inherit from BaseStorage's type-first implementation
   // Removed 2 pagination methods (getNounsWithPagination, getVerbsWithPagination) - use BaseStorage's implementation
 
-  public supportsMultiProcessLocking(): boolean {
+  public override supportsMultiProcessLocking(): boolean {
     return true
   }
 
@@ -1557,7 +1557,7 @@ export class FileSystemStorage extends BaseStorage {
    *      `lastHeartbeat` is older than `WRITER_STALE_THRESHOLD_MS` (60s).
    * Stale locks are overwritten with a warning. `force: true` overrides even live locks.
    */
-  public async acquireWriterLock(options?: { force?: boolean }): Promise<WriterLockInfo | null> {
+  public override async acquireWriterLock(options?: { force?: boolean }): Promise<WriterLockInfo | null> {
     await this.ensureInitialized()
     await this.ensureDirectoryExists(this.lockDir)
 
@@ -1639,7 +1639,7 @@ export class FileSystemStorage extends BaseStorage {
     return info
   }
 
-  public async releaseWriterLock(): Promise<void> {
+  public override async releaseWriterLock(): Promise<void> {
     if (this.writerLockHeartbeat) {
       clearInterval(this.writerLockHeartbeat)
       this.writerLockHeartbeat = undefined
@@ -1664,7 +1664,7 @@ export class FileSystemStorage extends BaseStorage {
     }
   }
 
-  public async readWriterLock(): Promise<WriterLockInfo | null> {
+  public override async readWriterLock(): Promise<WriterLockInfo | null> {
     await this.ensureInitialized()
     const lockFile = path.join(this.lockDir, FileSystemStorage.WRITER_LOCK_FILE)
     try {
@@ -1749,7 +1749,7 @@ export class FileSystemStorage extends BaseStorage {
    * `locks/_flush_responses/` with the same request ID. Stale `.req` files
    * (>FLUSH_REQUEST_TTL_MS) are garbage-collected on every tick.
    */
-  public startFlushRequestWatcher(onRequest: () => Promise<void>): void {
+  public override startFlushRequestWatcher(onRequest: () => Promise<void>): void {
     if (this.flushWatcherInterval) return // already watching
     this.flushWatcherOnRequest = onRequest
 
@@ -1772,7 +1772,7 @@ export class FileSystemStorage extends BaseStorage {
     }
   }
 
-  public stopFlushRequestWatcher(): void {
+  public override stopFlushRequestWatcher(): void {
     if (this.flushWatcherInterval) {
       clearInterval(this.flushWatcherInterval)
       this.flushWatcherInterval = undefined
@@ -1851,7 +1851,7 @@ export class FileSystemStorage extends BaseStorage {
    * Inspector side: drop a `.req` file and poll for the corresponding `.ack`.
    * Returns true if the writer acknowledged in time, false on timeout.
    */
-  public async requestFlushOverFilesystem(timeoutMs: number): Promise<boolean> {
+  public override async requestFlushOverFilesystem(timeoutMs: number): Promise<boolean> {
     await this.ensureInitialized()
     const reqDir = path.join(this.lockDir, FileSystemStorage.FLUSH_REQUEST_DIR)
     const ackDir = path.join(this.lockDir, FileSystemStorage.FLUSH_RESPONSE_DIR)