### What happened

On Apple T2 Macs (`MacBookPro16,1`, 2019 16"), no battery charge-limit feature can work,
because Linux has **no SMC access at all** on this hardware — and nothing in Omarchy
currently surfaces that, so the machine looks like an ordinary laptop that just
happens to be missing the sysfs knob.

Charge limiting is a firmware function: software cannot refuse power arriving from
the charger, only the SMC can hold the pack at a target level. On pre-T2 Intel Macs the
SMC was reachable on the legacy `0x300` I/O port and `applesmc` could write the `BCLM`
key. On T2 Macs the SMC moved behind the T2 coprocessor, and no in-tree or
out-of-tree driver implements that transport. `applesmc` therefore probes, finds no
legacy device, and binds nothing.

This is a hardware-support gap rather than an Omarchy bug, but it has two concrete
consequences for Omarchy that are worth tracking:

1. Charge-limit support (previously requested in #3036 / #1289) can never apply to this
   class of machine, and any future implementation will need to degrade cleanly rather
   than assume `charge_control_end_threshold` exists.
2. There's currently no way for a T2 user to discover *why* it doesn't work. A
   hardware-capability note (or a line in the power panel / `omarchy-battery-*` output)
   would save people a long dig through sysfs.

### Evidence

```console
$ cat /sys/class/dmi/id/product_name
MacBookPro16,1

$ uname -r
7.1.8-arch1-Watanare-T2-3-t2

$ ls /sys/class/power_supply/BAT0/
alarm  capacity  charge_full  charge_full_design  charge_now  current_avg
current_now  cycle_count  device  extensions  hwmon4  manufacturer  model_name
power  present  status  subsystem  technology  temp  type  uevent
voltage_min_design  voltage_now  wakeup68
# no charge_control_start_threshold / charge_control_end_threshold / charge_behaviour

$ find /sys -maxdepth 5 -iname '*charge_control*'
# (no output)

$ readlink -f /sys/class/power_supply/BAT0/device
/sys/devices/LNXSYSTM:00/.../ACPI0001:00/ACPI0002:00
# plain ACPI battery — read-only, no control method in Apple's DSDT

$ lsmod | grep applesmc
applesmc               45056  0          # refcount 0

$ ls /sys/bus/platform/drivers/applesmc
ls: cannot access '/sys/bus/platform/drivers/applesmc': No such file or directory
# module loaded, zero devices bound: the legacy SMC I/O port is absent on T2

$ lsmod | grep t2bce
t2bce_audio  t2bce_vhci  t2bce_core  t2bce_dma
# the T2 stack implements audio + VHCI only; no SMC key transport, no chardev
```

### Why the usual workaround doesn't apply

The standard advice for Intel Macs is to boot macOS once, write `BCLM=80` with a tool
like [zackelia/bclm](https://github.com/zackelia/bclm), and let the SMC enforce it
persistently under any OS. That only helps dual-boot users — on a
wiped, Linux-only T2 Mac there is no macOS partition left to boot, and no way back
in short of reinstalling macOS.

### What would help

Broadly, better T2 MacBook support. Specifically for this area:

- Treat charge limiting as an explicitly hardware-gated feature: detect the absence of
  `charge_control_end_threshold` and say *why* on Apple T2 hardware, rather than
  silently offering nothing.
- If a `battery-high` / unplug-reminder hook ever lands alongside the existing
  `battery-low.d` hooks, it would be the only usable substitute on this hardware.

### System

- Omarchy `4.0.0.alpha`
- `MacBookPro16,1` (Apple T2)
- Kernel `7.1.8-arch1-Watanare-T2-3-t2`
- Battery `bq40z651` (SMP), 112 cycles, `charge_full` 7079000 / `charge_full_design` 8790000