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

local/docs/PROFILE-MATRIX.md

@@ -27,9 +27,8 @@ USB plan uses:
 | Profile | Intent | Key Fragments | Current support language |
 |---|---|---|---|
 | `redbear-mini` | Console + storage + wired-network baseline | `minimal.toml`, `redbear-legacy-base.toml`, `redbear-device-services.toml`, `redbear-netctl.toml` | builds / primary validation baseline / DHCP boot profile enabled / input-runtime substrate wired / USB: daemons built via base and targeted for bounded mini-profile validation |
-| `redbear-live-mini` | Live/recovery form of the mini baseline | `redbear-live-minimal.toml`, `redbear-minimal.toml` | builds / live media variant of the mini profile for real bare metal / desktop graphics intentionally absent |
+| `redbear-grub` | Text-only with GRUB boot manager | `redbear-mini.toml`, `redbear-grub-policy.toml` | builds / live media variant with GRUB chainload for real bare metal / desktop graphics intentionally absent |
 | `redbear-full` | Desktop/network/session plumbing target | `desktop.toml`, `redbear-legacy-base.toml`, `redbear-legacy-desktop.toml`, `redbear-device-services.toml`, `redbear-netctl.toml`, `redbear-greeter-services.toml` | builds / boots in QEMU / active desktop-capable compile target / support claims remain evidence-qualified |
-| `redbear-live-full` | Live/recovery form of the full desktop target | `redbear-live-full.toml`, `redbear-full.toml` | builds / live desktop-capable image for real bare metal / inherits the full target surface |
 
 ## Profile Notes
 
@@ -46,9 +45,10 @@ USB plan uses:
   are bounded validation slices layered on top of the tracked compile targets, not additional
   compile targets.
 
-### `redbear-live-mini`
+### `redbear-grub`
 
-- Carries the same bounded non-graphics intent as `redbear-mini`, but in live/recovery image form.
+- Text-only console/recovery target with GRUB boot manager for multi-boot bare-metal workflows.
+- Inherits the same non-graphics intent as `redbear-mini`, but with GRUB chainload ESP layout.
 - Should not grow desktop/session assumptions.
 
 ### `redbear-full`
@@ -56,22 +56,17 @@ USB plan uses:
 - Desktop-capable tracked target for the current Red Bear session/network/runtime plumbing surface.
 - Carries the broader D-Bus, greeter, seat, and desktop-oriented service surface.
 
-### `redbear-live-full`
-
-- Live/demo/recovery form of the full desktop-capable target.
-- Inherits the same desktop-target assumptions as `redbear-full`, but for live media workflows.
-
 ### Historical notes
 
-- Older names such as `redbear-minimal`, `redbear-desktop`, `redbear-wayland`, `redbear-kde`, and
-  `redbear-live` remain in older docs and some implementation details, but they are not the current
-  supported compile-target surface.
+- Older names such as `redbear-minimal`, `redbear-desktop`, `redbear-wayland`, `redbear-kde`,
+  `redbear-live`, `redbear-live-mini`, and `redbear-live-full` remain in older docs and some
+  implementation details, but they are not the current supported compile-target surface.
 
 ### `redbear-bluetooth-experimental`
 
 - Standalone tracked profile for the first in-tree Bluetooth slice instead of a blanket claim about
   all Red Bear images.
-- Extends `redbear-minimal` so the baseline runtime tooling is already present, then adds only the
+- Extends `redbear-mini` so the baseline runtime tooling is already present, then adds only the
   bounded Bluetooth pieces on top.
 - Current path under active validation: QEMU/UEFI boot to login prompt plus guest-side `redbear-bluetooth-battery-check`, targeting repeated in-boot reruns, daemon-restart coverage, and one experimental battery-sensor Battery Level read-only workload.
 - Current support language is intentionally narrow: explicit-startup only, USB-attached transport,
@@ -82,7 +77,7 @@ USB plan uses:
 
 - Standalone tracked profile for the current bounded Intel Wi-Fi slice instead of implying that the
   wider desktop profiles already carry the full driver stack.
-- Extends `redbear-minimal` so the baseline firmware/input/reporting/profile-manager surface stays
+- Extends `redbear-mini` so the baseline firmware/input/reporting/profile-manager surface stays
   inherited while the Intel Wi-Fi driver package and bounded validation role remain isolated here.
 - Includes the Intel driver package (`redbear-iwlwifi`) in addition to the shared firmware,
   control-plane, reporting, and profile-manager pieces.
@@ -109,6 +104,6 @@ USB plan uses:
 - USB error handling and correctness carry significant Red Bear patches over upstream; see
   `local/patches/base/redox.patch` and `local/docs/USB-IMPLEMENTATION-PLAN.md` for details.
 - The in-tree mini image is still assembled through legacy `redbear-minimal*` config files in some
-  places, but the supported compile-target names are `redbear-mini` and `redbear-live-mini`.
+  places, but the supported compile-target names are `redbear-mini` and `redbear-grub`.
 - `redbear-bluetooth-experimental` uses USB only as a transport for BLE dongles; it does not make a
   general USB-class-autospawn claim.