README: fix Go version, drop dead v0.1.1 examples, add report to Key Features

[jigarkhwar]

Part of galaxio-ai-sdlc Decision DEC-9102 (ecosystem baseline hardening), task
T-018. README-only, kept separate from #130.

• Stated Go requirement was 1.24; go.mod hard-enforces 1.27.1.
• Three copy-paste examples (installer, docker pull, update --version) hardcoded
  0.1.1, a version that was never tagged or released. Replaced with a
  <version> placeholder, matching the convention the Docker section already uses
  for <release-version>/<major.minor>.
• report -- the most actively developed command family, extensively documented
  further down the README -- was missing from the Key Features overview.