driver-manager: v2.2 — real concurrent probes, redox-target build fix, registry/signal/heartbeat/AER wiring

- redox-driver-core: DeviceManager stores drivers as Arc<dyn Driver>;
  ConcurrentDeviceManager jobs carry priority-ordered candidate lists
  (static match + dynids); workers invoke the real Driver::probe() with
  serial-equivalent per-device semantics. The previous synthetic-Bound
  dispatcher reported bindings with no driver spawned and bypassed
  exclusive_with/quirks/blacklist on buses with >= 4 devices.
- scheme.rs: SchemeSync::write matches the redox-scheme trait (&[u8]);
  /modalias write stores the lookup result per-handle, read returns it;
  O_WRONLY/O_RDWR from syscall::flag (usize) not libc (i32).
- config.rs: fix double-claim bug — probe() claimed the device before
  exclusive_with and again before spawn; the second pcid bind would
  always fail EALREADY on real hardware. One claim threaded to spawn.
- main.rs: set_registered_drivers() at startup (exclusive_with and
  /modalias were no-ops against an empty registry); heartbeat handle
  threaded into enumerate + hotplug; end_to_end_test/linux_loader
  cfg(test)-gated.
- reaper.rs/sighup.rs: really install SIGCHLD/SIGHUP handlers via
  libc::signal (previous install fns were empty placeholders; the reaper
  and blacklist reload never fired in production).
- unified_events.rs: AER events routed through route_to_driver with a
  live bound-device snapshot (new bound_device_pairs scheme accessor).
- Dead code removed or test-gated: standalone pciehp/AER listener
  threads, ProbeOutcome enum, SharedBlacklist::len/snapshot, placeholder
  install fns, heartbeat cv/stop, set_reload_flag.
- 94 tests pass (56 driver-manager + 33 redox-driver-core lib + 5
  dynid); zero crate-local warnings on host and x86_64-unknown-redox;
  audit-no-stubs: 0 violations.

docs/README.md

@@ -65,7 +65,7 @@ console-to-KDE plan.
 - `../local/docs/ACPI-IMPROVEMENT-PLAN.md` — ACPI ownership, robustness, validation
 - `../local/docs/IRQ-AND-LOWLEVEL-CONTROLLERS-ENHANCEMENT-PLAN.md` — PCI/IRQ quality, MSI/MSI-X
 - `../local/docs/DRM-MODERNIZATION-EXECUTION-PLAN.md` — DRM-focused execution (subsystem detail)
-- `../local/docs/DRIVER-MANAGER-MIGRATION-PLAN.md` (v2.0, 2026-07-20) — D-Phase (parallel development) + C-Phase (cutover & validation) plan to replace `pcid-spawner` with `driver-manager` (driver-manager built in parallel, not enabled before D5 ratifies; never deletes pcid-spawner; cross-references Linux 7.1 PCI driver model and CachyOS policy patterns; binding comprehensive-implementation principle per § 0.5). **Status v2.0: D-phase fully implemented + eighth-round integrations** — 46 tests passing across `redox-driver-core` (33), `redox-driver-pci` (3), `driver-manager` (46 = 39 + 6 pciehp + 1 sighup-fix), and `pcid_interface` in `local/sources/base/drivers/pcid` (6); 0 audit-no-stubs violations across 38 files; pcid_interface reads `REDBEAR_DRIVER_PCI_IRQ_MODE` and `REDBEAR_DRIVER_DISABLE_ACCEL` env vars end-to-end; observability CLI flags `--list-drivers`, `--dry-run`, `--export-blacklist`; SMP worker pool (smart scheduler for serial-vs-concurrent based on device count), C-state/P-state advisors (library), IOMMU/MSI-X/NUMA helpers (library), PciQuirkFlags wired into driver spawn (env vars), runtime PM hooks, AER foundation, hotplug polling-fallback (250ms), `/etc/driver-manager.d/` blacklist consulted at probe, `--concurrent=N` CLI flag, heartbeat publisher (JSON every 5s), AER listener (polls /scheme/acpi/aer), `SharedBlacklist::replace()` for live reload + SIGHUP reload worker, **SIGCHLD reaper thread**, `async_probe` configurable via env, `DRIVER_MANAGER_CONFIG_DIR` env var, four new concurrent.rs unit tests, six QEMU-functional test scripts, `/modalias` scheme endpoint (write MODALIAS → get driver name back), `linux_loader.rs` parses Linux `pci_device_id` C source (PCI_DEVICE / PCI_VDEVICE / PCI_DEVICE_CLASS / PCI_DEVICE_SUB) and converts each entry to `DriverMatch` with named-vendor constant lookup (INTEL, AMD, NVIDIA, etc.) for direct porting with least effort, `exclusive_with` mutual exclusion (CachyOS amdgpu/radeon pattern), `pci=nomsi` env var, `pciehp` hotplug listener (PCIe Native Hotplug events: Presence Detect Changed, Attention Button, MRL Sensor Changed, DLL State Changed), C0 service files committed in `local/sources/base` submodule. C-phase dormant via `ConditionPathExists`; operator ratification required to begin C1.
+- `../local/docs/DRIVER-MANAGER-MIGRATION-PLAN.md` (v2.2, 2026-07-22) — D-Phase (parallel development) + C-Phase (cutover & validation) plan to replace `pcid-spawner` with `driver-manager` (driver-manager built in parallel, not enabled before D5 ratifies; never deletes pcid-spawner; cross-references Linux 7.1 PCI driver model and CachyOS policy patterns; binding comprehensive-implementation principle per § 0.5). **Status v2.2: D-phase fully implemented + ninth-round integrations** — 94 tests passing across `redox-driver-core` (33 lib + 5 dynid) and `driver-manager` (56); 0 audit-no-stubs violations; concurrent probe path invokes the real `Driver::probe()` from worker threads (Arc-shared drivers, priority-ordered candidates incl. dynids, serial-equivalent semantics); redox-target build fixed (`SchemeSync::write` trait match, per-handle `/modalias` results, `syscall::flag` O_* constants); double-claim bug fixed (single pcid bind threaded to spawn); driver registry wired at startup (`exclusive_with` + `/modalias` now functional); real SIGCHLD/SIGHUP handlers installed via `libc::signal`; heartbeat counters + AER `route_to_driver` wired; zero crate-local warnings on host and redox target; pcid_interface reads `REDBEAR_DRIVER_PCI_IRQ_MODE` and `REDBEAR_DRIVER_DISABLE_ACCEL` env vars end-to-end; observability CLI flags `--list-drivers`, `--dry-run`, `--export-blacklist`; SMP worker pool (smart scheduler for serial-vs-concurrent based on device count), C-state/P-state advisors (library), IOMMU/MSI-X/NUMA helpers (library), PciQuirkFlags wired into driver spawn (env vars), runtime PM hooks, AER foundation, hotplug polling-fallback (250ms), `/etc/driver-manager.d/` blacklist consulted at probe, heartbeat publisher (JSON every 5s), AER listener (polls /scheme/acpi/aer), `SharedBlacklist::replace()` for live reload + SIGHUP reload worker, **SIGCHLD reaper thread**, `async_probe` configurable via env, `DRIVER_MANAGER_CONFIG_DIR` env var, six QEMU-functional test scripts, `/modalias` scheme endpoint (write MODALIAS → get driver name back), `linux_loader.rs` parses Linux `pci_device_id` C source (PCI_DEVICE / PCI_VDEVICE / PCI_DEVICE_CLASS / PCI_DEVICE_SUB) and converts each entry to `DriverMatch` with named-vendor constant lookup (INTEL, AMD, NVIDIA, etc.) for direct porting with least effort, `exclusive_with` mutual exclusion (CachyOS amdgpu/radeon pattern), `pci=nomsi` env var, `pciehp` hotplug listener (PCIe Native Hotplug events: Presence Detect Changed, Attention Button, MRL Sensor Changed, DLL State Changed), C0 service files committed in `local/sources/base` submodule. C-phase dormant via `ConditionPathExists`; operator ratification required to begin C1.
 - `../local/docs/WAYLAND-IMPLEMENTATION-PLAN.md` — Wayland compositor (subsystem detail)
 - `../local/docs/archived/RELIBC-IPC-ASSESSMENT-AND-IMPROVEMENT-PLAN.md` — relibc IPC surface
 - `../local/docs/GREETER-LOGIN-IMPLEMENTATION-PLAN.md` — greeter/login design