fix(publish): drop --target from vsce publish (conflicts with --packagePath) (#27)

## Why

After #26 surfaced vsce's actual error (which the bash retry function
was previously eating), the diagnostic was clear. Reproduced locally by
downloading the failed run's `vsix-darwin-x64` artifact and running:

```
$ npx @vscode/vsce@^3 publish --target darwin-x64 --packagePath extension-darwin-x64.vsix --pat <fake>

 ERROR  Both options not supported simultaneously: 'packagePath' and 'target'.
        Use 'vsce package --target <target>' to first create a platform specific
        package, then use 'vsce publish --packagePath <path>' to publish it.
```

vsce reads the target from the `.vsix` manifest's `<TargetPlatform>` tag
(stamped at `vsce package --target` time) and explicitly rejects
`--target` together with `--packagePath`. The error fires before any
auth check, which is why all 4 vsce publishes failed in ~1 second flat.

ovsx is more permissive and accepts both flags together — that's why
every ovsx publish succeeded while every vsce publish failed
identically.

## Fix

Drop `--target ${{ matrix.target }}` from the `vsce publish` call. The
matrix still records the target via the step name, the artifact name,
the .vsix filename, and the manifest stamping — nothing self-documenting
is lost.

`ovsx publish --target ... --packagePath ...` is left as-is since ovsx
accepts both and the explicit `--target` round-trips through the ovsx
API for the registry's own metadata (and worked on the previous run for
all 4 targets).

## State going in

- **VS Code Marketplace:** still on `0.2.0`. `0.2.2` never landed.
- **Open VSX:** has `0.2.2` for all 4 targets.
- **#26 merged:** retry function now surfaces vsce/ovsx output
regardless of exit code.

## Recovery on merge

`prepare` will see Marketplace doesn't have `0.2.2` → proceeds. ovsx
will return "already exists" for all 4 targets → idempotent success.
vsce, with the conflicting flag removed, should publish all 4 targets
cleanly. `finalize` will tag and cut the GitHub Release.

## Test plan

- [x] Reproduced the error locally with the failed-run artifact
- [x] Confirmed `vsce publish --packagePath <vsix>` (without `--target`)
is the documented vsce form for publishing pre-packaged
platform-specific .vsix files
- [ ] After merge: push to main triggers re-run; vsce publishes all 4
targets to Marketplace; finalize creates `vscode-extension-v0.2.2` tag
and GitHub Release

Author: AlemTuzlak

.github/workflows/publish.yml

@@ -277,10 +277,13 @@ jobs:
             done
           }
 
-          # `--target` is read from the .vsix manifest (set at package time),
-          # but pass it explicitly to make the matrix entry self-documenting.
+          # vsce reads the target from the .vsix manifest (set at package
+          # time) and explicitly rejects `--target` together with
+          # `--packagePath` — quote: "Both options not supported
+          # simultaneously: 'packagePath' and 'target'." So pass only
+          # `--packagePath`. The matrix already records the target visibly
+          # in the step name and artifact name.
           retry_publish npx --yes @vscode/vsce@^3 publish \
-            --target ${{ matrix.target }} \
             --packagePath extension-${{ matrix.target }}.vsix \
             --azure-credential