v0.16.0 — fugo doctor: toolchain + project health

Smarter fugo doctor

Two sections now:

Toolchain — Go, Flutter, git, protoc, gofumpt (Go/Flutter required → ✗; rest are warnings) + platform.

Project (inside a Fugo project) — imports fugo.toml and validates what fugo run needs:

• resolved window + gRPC address from fugo.toml,
• the configured address is free (or a unix socket),
• structure (main.go, ui/, go.mod),
• the github.com/sazardev/fugo module resolves,
• the Flutter client is built (or buildable),
• the project compiles (go build ./...).

Exits non-zero on a blocking issue (missing required tool, unresolved module, or a project that doesn't compile) so it can gate scripts/CI; warnings alone keep a zero exit.

Full diff: v0.15.0...v0.16.0