Add initial ext2 read/write and formatting support

Register ext2 at boot, integrate mode-aware VFS opens and volume cleanup, and queue asynchronous transfers through a persistent worker.

Validation: Pascal compiler check and git diff --check passed. Full build blocked by Docker engine HTTP 500; runtime and Linux interoperability remain unverified.

src/boot/boot.mgr.pas

@@ -96,6 +96,7 @@ uses
     driver.net.dev.e1000,
     driver.bus.usb.ehci,
     driver.storage.fs.fat32,
+    driver.storage.fs.ext2,
     arch.x86.fault,
     core.ds.fifo,
     driver.storage.fs.mgr,
@@ -562,4 +563,4 @@ initialization
       EntryCount would silently discard their registrations. }
     registerBoot('boot.mgr.debug', @printBootEntriesTree, 'Debug: Print Boot Entries Tree', 'io.syslog');
 
-end.
+end.