fix: code quality improvements vet target, bug fixes, and typo corrections

[patilpratik1905]

Description

Changes

1. Add vet target to Makefile

Added make vet target that runs go vet ./... across all packages.
Enables standardized static analysis locally and in CI pipelines.

2. Fix fmt.Errorf result not used (pkg/watcher/executor.go)

fmt.Errorf(...) was called but its return value was discarded, silently
swallowing the error. Replaced with fmt.Printf(...) so the error is
actually printed to output.

3. Fix DownloadArtifact reading wrong body (pkg/connectors/microcks_client.go)

io.ReadAll(req.Body) was reading the request body instead of the response
body after the HTTP call completed. This caused the function to always return
empty data. Fixed to io.ReadAll(resp.Body).

4. Fix function name typo (pkg/connectors/microcks_client.go)

Renamed ensureValieOAuth2Context → ensureValidOAuth2Context.
Updated both the function definition and its call site.

Testing

• make vet now passes with no errors

Related issue(s)

NA

[github-actions]

👋 @patilpratik1905

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[Caesarsage]

The typos are covered by #300 and CI now runs go test — but the make vet idea is still good and aligns with #355. Suggest re-scoping this PR to just the vet target (or folding it into a CI-gates PR alongside staticcheck).

[Harsh4902]

Thanks @Caesarsage for your review. @patilpratik1905 I'm keeping this PR open and waiting for your update.