- Add Go-specific analysis prompt in .grokkit/prompts/go.md
- Expand cmd/analyze.go to discover files, detect language, load prompts, build context, generate report via Grok, and handle output with preview/confirmation
- Integrate analyzeCmd into root command
- Introduce internal/linter/language.go for primary language detection
- Add internal/prompts/analyze.go for loading analysis prompts from project or global locations
Introduces a new Cobra command `analyze` that performs deep project analysis,
discovers files, builds context, streams to Grok for report generation, and
handles output with confirmation.
