docs(roadmap): add v1.1 ai-native matrix

[typelicious]

What changed

• add a dedicated AI-native client matrix for the first post-1.0 block
• update the roadmap to define v1.1.0 around AI-native client expansion, usage visibility, and routing review
• link the matrix from the root README resources section

Why

• we need a disciplined shortlist before building more starter templates
• this keeps v1.1 small enough to ship while still helping FoundryGate discovery and adoption
• it also separates true template candidates from framework/platforms that should stay matrix-only for now

How verified

• checked the matrix against current public GitHub repo stars and recent activity on 2026-03-15
• /usr/bin/git diff --check