D-Bus Phase 3/4: upgrade sessiond, services, add StatusNotifierWatcher, consolidate configs

- redbear-sessiond: add Manager.Inhibit (pipe FD), CanPowerOff/CanReboot/
  CanSuspend/CanHibernate/CanHybridSleep/CanSleep (return na), PowerOff/
  Reboot/Suspend stubs, GetSessionByPID, ListUsers, ListSeats,
  ListInhibitors, ActivateSession/LockSession/UnlockSession/TerminateSession
- redbear-sessiond: add Session SetIdleHint, SetLockedHint, SetType,
  Terminate methods; wire PauseDevice/ResumeDevice/Lock/Unlock signal
  emission via SignalEmitter injection; add dynamic device enumeration
  scanning /scheme/drm/card* and /dev/input/event* at startup
- redbear-sessiond: replace infinite pending() with stoppable shutdown
  via tokio watch channel + control socket shutdown command
- redbear-upower: add Changed signal emission with 30s periodic polling
  and power state snapshot comparison
- redbear-notifications: add ActionInvoked signal, expand capabilities
  to body + body-markup + actions
- redbear-polkit, redbear-udisks: replace pending() with stoppable
  shutdown via signal handling + watch channel
- Add redbear-statusnotifierwatcher: new session bus service implementing
  org.freedesktop.StatusNotifierWatcher for KDE system tray
- Add D-Bus activation file for StatusNotifierWatcher
- KWin session.cpp: try LogindSession before NoopSession fallback
- Consolidate config profiles: remove obsolete redbear-desktop, redbear-kde,
  redbear-live-*, redbear-minimal-*, redbear-wayland configs; simplify
  to three supported targets (redbear-full, redbear-mini, redbear-grub)
- Update DBUS-INTEGRATION-PLAN.md and DESKTOP-STACK-CURRENT-STATUS.md
  with Phase 3/4 fragility assessment, KWin readiness matrix, and
  completeness gap analysis

docs/README.md

@@ -107,8 +107,8 @@ This summary is only a quick orientation layer. For canonical current-state deta
 - `local/docs/PROFILE-MATRIX.md` for support-language by tracked profile,
 - and the active subsystem plans under `local/docs/` for detailed current workstreams.
 
-- **Compile targets**: the supported compile targets are `redbear-mini`, `redbear-live-mini`, `redbear-full`, and `redbear-live-full`
-- **Live ISO policy**: live `.iso` outputs (`redbear-live-mini`, `redbear-live-full`) are for real bare-metal boot/install/recovery workflows, not the VM/QEMU execution surface.
+- **Compile targets**: the supported compile targets are `redbear-mini`, `redbear-full`, and `redbear-grub`
+- **Live ISO policy**: live `.iso` outputs (`make live`) are for real bare-metal boot/install/recovery workflows, not the VM/QEMU execution surface.
 - **Wayland**: libwayland + wayland-protocols built. A bounded greeter/compositor-backed login proof now passes, but broader compositor/runtime stability remains incomplete.
 - **Qt6**: qtbase 6.11.0 (Core+Gui+Widgets+DBus+Wayland), qtdeclarative, qtsvg, qtwayland ALL BUILT
 - **D-Bus**: 1.16.2 built for Redox. Qt6DBus enabled.
@@ -120,7 +120,7 @@ This summary is only a quick orientation layer. For canonical current-state deta
 - **PCI / IRQ quality**: architecturally strong substrate exists, with bounded MSI-X, IOMMU, xHCI IRQ, and low-level-controller proof surfaces; broader hardware robustness is still intentionally tracked as open work in `../local/docs/IRQ-AND-LOWLEVEL-CONTROLLERS-ENHANCEMENT-PLAN.md`
 - **Wi-Fi profile target**: `config/redbear-wifi-experimental.toml` is the first explicit tracked image slice for bounded Intel Wi‑Fi validation, instead of spreading that claim across the generic desktop profiles.
 - **Bluetooth**: one bounded in-tree BLE-first experimental slice exists, and the Battery Level read-only workload now has a packaged in-guest checker plus a host QEMU harness; QEMU validation is still in progress, so broad desktop Bluetooth parity is still incomplete
-- **Desktop direction**: `redbear-full` / `redbear-live-full` carry the desktop-capable target surface; the bounded greeter/login slice now passes, while the wider desktop runtime stack is still incomplete.
+- **Desktop direction**: `redbear-full` carries the desktop-capable target surface; the bounded greeter/login slice now passes, while the wider desktop runtime stack is still incomplete.
 - **ACPI**: materially complete for the historical boot baseline, not release-grade complete; implemented: AML mutex real state, EC widened accesses via byte transactions, kstop-based shutdown eventing, explicit `RSDP_ADDR` forwarding into `acpid`, x86 BIOS-search AML fallback, and real-but-provisional AML-backed power enumeration. **Known gaps**: the explicit boot-path producer contract for AML bootstrap is still underdocumented, `acpid` startup hardening remains open, shutdown/power reporting are still provisional, sleep state transitions and sleep eventing remain incomplete, DMAR ownership is still transitional, and bare-metal validation is still bounded. See `local/docs/ACPI-IMPROVEMENT-PLAN.md`.
 - **Linux driver compat**: linux-kpi now includes early wireless-subsystem compatibility scaffolding in addition to the earlier helper layer, redox-driver-sys and firmware-loader compile, and the bounded Intel Wi-Fi path now has host-tested scan/connect/disconnect/profile/reporting flows without claiming real hardware Wi-Fi connectivity.
 - **Wi-Fi validation tooling**: `redbear-phase5-wifi-check` and `redbear-phase5-wifi-capture` are now packaged in-guest helpers for bounded Intel Wi-Fi runtime validation and evidence capture on bare metal or VFIO-backed guests.