📝 Release: Docs and Changelog polish

[jongalloway]

Polish README/docs for Beta 1.0 and add CHANGELOG entry.

Tasks

• Update README with quickstart (NuGet + Demo container)
• Document config basics (List/Summarize/Generate, MCP note)
• Add troubleshooting for common setup issues
• Write CHANGELOG.md section for 1.0.0-beta.1

Acceptance Criteria

• New users can install and run the demo in <10 minutes
• Clear changelog entry for the release

Parent: #76

[jongalloway]

Onboarding note: This is a great first contribution. Pure docs/markdown changes. Suggested steps:

1. Skim doc/README.md and doc/demo-setup-guide.md for context.
2. Add a "Quickstart" to the root README.md (NuGet + Docker demo).
3. Create/extend a Troubleshooting section with 2-3 common restore/build issues (NuGet feeds, SDK version, Docker restore).
4. Add a new section to CHANGELOG.md titled 1.0.0-beta.1 with bullets pulled from 🚢 Release: 1.0.0-beta.1 (stabilize and ship) #76.

Acceptance check: A new user can install the package, run the demo in <10 minutes, and see the new changelog entry.

Ping here if any context is unclear; we can point you to the exact docs to mirror.