[bug] Version mismatch: image ships with linux-image 26.2.1 but headers 26.2.1 unavailable in 'current' repo (rockchip64)

[untitledds]

Armbianmonitor:

https://paste.armbian.com/jojezekiko

## Description
After a fresh installation of Armbian for Rockchip64 (Rock 3A), the system ships with `linux-image-current-rockchip64` version **26.2.1** (kernel 6.18.8), but the corresponding `linux-headers-current-rockchip64` package for version 26.2.1 is **not available** in the public APT repositories.

This prevents installation of kernel headers required for DKMS modules, out-of-tree drivers, or any kernel module compilation.

## Steps to Reproduce
1. Flash the latest Armbian image for `rock-3a` (branch: `current`) from the official download page.
2. Boot the device and connect to the network.
3. Run `apt update` with any standard mirror (e.g., `mirrors.tuna.tsinghua.edu.cn`, `mirror.yandex.ru`).
4. Check installed kernel version:
   ```bash
   uname -r
   # Output: 6.18.8-current-rockchip64
   ```
5. Check available headers:
   ```bash
   apt policy linux-headers-current-rockchip64
   ```

## Actual Behavior
- Installed image packages:
  ```
  linux-image-current-rockchip64  26.2.1  [installed,local]
  linux-dtb-current-rockchip64    26.2.1  [installed,local]
  armbian-bsp-cli-rock-3a-current 26.2.1  [installed]
  ```
- `apt policy` output for headers:
  ```
  linux-headers-current-rockchip64:
    Installed: (none)
    Candidate: 25.11.2
    Version table:
       25.11.2 500
          500 http://<mirror>/armbian noble/main arm64 Packages
       ... (no 26.2.1 available)
  ```

## Expected Behavior
- The `linux-headers-current-rockchip64` package version **26.2.1** should be available in the `current` branch repository, matching the kernel shipped in the image.
- Alternatively, the image should ship with packages that are already published and synchronized in the public repository.

## Impact
- Users cannot install DKMS modules (ZFS, VirtualBox, WiFi drivers, etc.).
- Development workflows requiring kernel headers are blocked.
- Confusion for users performing a "clean install" who expect a consistent system.

## System Information
- **Board:** Radxa Rock 3A
- **Armbian version:** 26.2.1 (from image filename/release)
- **Kernel:** 6.18.8-current-rockchip64
- **APT branch:** `current`
- **Distribution:** Ubuntu Noble (24.04)
- **Mirrors tested:** 
  - `http://mirrors.tuna.tsinghua.edu.cn/armbian`
  - `http://mirror.yandex.ru/mirrors/armbian/apt`
  - `http://apt.armbian.com` (redirector)

## Possible Causes (hypothesis)
1. **Publishing race condition:** The image was built after `linux-image-26.2.1` was compiled but before `linux-headers-26.2.1` was published to the public repository.
2. **Branch mislabeling:** Version 26.2.1 may have been moved to `edge` after the image was built, but the image metadata was not updated.
3. **Mirror sync delay:** The master repository has the package, but mirrors have not yet synchronized (though multiple mirrors were tested over several days).