feature: boot.mgr replace hardcoded init sequence with dependency-driven boot manager

Introduce boot.mgr - a self-registering, dependency-ordered boot
initialization framework with barrier-based phasing and glob pattern
matching. Units now declare their own init procedures and dependencies
via registerBoot()/registerBarrier() in their initialization sections,
boot.mgr.run() topologically sorts and executes them.

- Add src/boot/boot.mgr.pas with topoSort, glob matching, barrier
  two-pass algorithm, and boot tree printer
- Gut src/asuro.pas (kmain): now just stores multiboot info, calls
  System.init(), boot.mgr.run, and yield()
- Add initialization sections with registerBoot() to 53 existing units
- Add new units: core.pas, test.pas, driver.storage.boot.pas,
  app.wasm.pas, app.bsod.pas (factored out of asuro.pas)
- Define 9 barrier phases: immediate -> early -> middle -> storage ->
  bus -> device -> bus.late -> late -> final
- Fix xHCI ISR: exclude PRC/WRC from PORTSC change bit clearing to
  prevent race with port reset busy-wait
- Fix driver.bus.usb.core fire_completion_hooks: guard against uint32
  underflow when CompletionHookCount = 0
- Move auto_mount_volumes from device barrier to late barrier so it
  runs after PCI scan discovers storage controllers
- Add toolchain/compile_initcalls.sh for boot entry extraction
- Add Boot Registration sections to all 51 doc files; create 4 new
  doc files; rewrite boot.mgr.md; update mkdocs.yml nav

doc/src/driver/storage/ctl/driver.storage.ctl.usb.md

@@ -8,8 +8,14 @@ This unit registers a USB class driver with the driver manager (`driver.mgr`) to
 
 Full Bulk-Only Transport (BOT) support — including Max LUN query, endpoint setup, CBW/CSW command exchange, and `driver.storage.mgr` device registration — is planned but not yet implemented.
 
+## Boot Registration
+
+Registered with `boot.mgr` as `driver.storage.ctl.usb` at the `device` barrier. The barrier order places `device` after `bus`, ensuring `driver.bus.usb.core.init` has run before the storage class driver registers with the driver manager.
+
 ## Dependencies
 
+- `boot.mgr`
+
 - `driver.mgr`
 - `memory.heap`
 - `driver.storage.types`