Add install smoke tests for go install, release artifacts, and Homebrew formula

[andreagrandi]

Closes #19.

This PR adds automated smoke tests for the documented install paths and release artifacts, plus release verification documentation.

Changes

• Add with three jobs:
  • : builds via and verifies and .
  • : runs GoReleaser in snapshot mode, executes the Linux amd64 binary, and verifies all expected archives and checksums exist.
  • : generates the Homebrew formula and syntax-checks it with Syntax OK.
• Add ==> Smoke testing go install from local source...
  go install smoke test passed
  ==> Smoke testing release artifacts with GoReleaser snapshot...
  release artifacts smoke test passed
  ==> All install smoke tests passed for local runs and wire it to ==> Smoke testing go install from local source...
  go install smoke test passed
  ==> Smoke testing release artifacts with GoReleaser snapshot...
  release artifacts smoke test passed
  ==> All install smoke tests passed.
• Add with automated smoke test summary and manual post-release verification steps for , Homebrew, and binary downloads.
• Update release process to reference .
• Update .

Verification

• ok github.com/andreagrandi/mb-cli/tests 2.819s
  ? github.com/andreagrandi/mb-cli/internal/cli [no test files]
  ? github.com/andreagrandi/mb-cli/internal/client [no test files]
  ? github.com/andreagrandi/mb-cli/internal/config [no test files]
  ? github.com/andreagrandi/mb-cli/internal/formatter [no test files]
  ? github.com/andreagrandi/mb-cli/internal/mberr [no test files]
  ? github.com/andreagrandi/mb-cli/internal/validation [no test files]
  ? github.com/andreagrandi/mb-cli/internal/version [no test files] and pass.
• passes on all workflow files.
• passes on the smoke test script.
• ==> Smoke testing go install from local source...
  go install smoke test passed
  ==> Smoke testing release artifacts with GoReleaser snapshot...
  release artifacts smoke test passed
  ==> All install smoke tests passed passes locally.