Add build-time grammar conflict analysis to participle

Normalized profile

What this task asks for

Add build-time static analysis that detects ambiguous participle grammars and reports conflicts. Add build-tagged grammar conflict types and analysis APIs while leaving new symbols unavailable without the analyze tag. Populate every conflict with type, severity, location, message, grammar snippet, example, and actionable suggestion. Provide immutable report filtering, counting, formatting, merging, and deduplication operations. Let parsers analyze with optional conflict suppression and let `StrictMode` reject every reported conflict during build. Detect first-first, first-follow, and unreachable alternatives with the specified severity and token-overlap rules. Suppress analysis inside lookahead groups and treat negation nodes as conflict-free.