docs: clarify alias and 1.0 scope

[vmvarela]

Summary

• Explain when native concrete model IDs are enough and when floating aliases help.
• Document inspection, change visibility, plugin ordering, explicit non-goals, and the 1.0 boundary.
• Keep deferred backlog work outside 1.0 without presenting a partial inventory as exhaustive.

Closes #30

Validation

• pnpm run verify
• pnpm run check:release
• git diff --check