ci: publish the cli extension into 2026/next, not 2026/edge (#237)

## What

`ext-release.yml` publishes `avocado-ext-cli` into `2026/edge` while
every other extension repo — and this repo's own 2024 leg — publishes
into `next`. `next` is the feed `avocado install` follows, so the last
two CLI releases never reached the users of the 2026 feed:

```
2026/edge  avocado-ext-cli 0.41.2-r0, 1.0.0~rc.2-r0, 1.0.0~rc.3-r0
2026/next  avocado-ext-cli 0.41.2-r0
```

`ext-test.yml` built only against 2024 (x86-64 and arm64), so nothing
exercised the 2026 feed before a tag went out.

## How

The 2026 release leg targets `next`. `ext-test.yml` gains the matching
`2026/next` leg on qemux86-64, so both feeds the release publishes into
are built before a tag.

## Results

rc.3 was republished into `2026/next` by dispatching this branch's
workflow (run
[33794740049](https://github.com/avocado-linux/avocado-cli/actions/runs/33794740049))
— "Published avocado-ext-cli-1.0.0-rc.3; ingest queued". The 2024 leg of
that dispatch failed as expected: rc.3 is already published there, and
the server rejects a duplicate version ("that extension version is
already taken").

rc.2 is left where it is; it is superseded.

Author: mobileoverlord

.github/workflows/ext-release.yml

@@ -48,7 +48,7 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - { target: qemux86-64, distro-release: "2026", distro-channel: edge }
+          - { target: qemux86-64, distro-release: "2026", distro-channel: next }
           - { target: qemux86-64, distro-release: "2024", distro-channel: next }
     uses: avocado-linux/actions/.github/workflows/extension-release.yml@v1
     with:

.github/workflows/ext-test.yml

@@ -43,6 +43,9 @@ jobs:
       matrix:
         include:
           - { target: qemux86-64, distro-release: "2024", distro-channel: next }
+          # Both feeds the release publishes into get a build leg, so a package
+          # that only breaks on one is caught before the tag.
+          - { target: qemux86-64, distro-release: "2026", distro-channel: next }
           # Keep a cross-arch leg. A same-arch target cannot catch a host/target
           # toolchain mix-up in avocado-cli-compile.sh: on qemux86-64 the target
           # gcc runs natively, so picking the wrong one still builds. On aarch64