docs: Consolidate compiler architecture into comprehensive guide

Merged and enhanced compiler architecture documentation:

- Consolidated Grue_Compiler_Architecture.md and
  GRUE_COMPILER_EXECUTION_ARCHITECTURE.md into single comprehensive
  COMPILER_ARCHITECTURE.md (1,231 lines)

- Added complete grammar pattern processing flow with concrete examples:
  * Source code → Tokens → AST → IR → Z-Machine bytecode transformation
  * Detailed data structure representations at each compilation stage
  * Runtime execution flow with parse buffer integration
  * Pattern matching strategy and ordering

- Complete example tracing "at" + noun => examine($2) through all phases:
  * Lexer tokenization
  * Parser AST construction
  * Semantic analysis and IR generation
  * Code generation with bytecode layout
  * Runtime pattern matching and handler execution

- Preserved separation of concerns:
  * COMPILER_ARCHITECTURE.md - comprehensive architecture guide
  * COMPILER_BUG_PATTERNS.md - gotchas and common mistakes
  * GRAMMAR_PATTERN_MATCHING_ANALYSIS.md - deep technical dive
  * DEVELOPER_ARCHITECTURE_GUIDE.md - platform-wide overview

- Archived original docs for reference:
  * ARCHIVE_Grue_Compiler_Architecture.md
  * ARCHIVE_GRUE_COMPILER_EXECUTION_ARCHITECTURE.md

Benefits:
- Single source of truth for compiler architecture
- Complete grammar transformation flow with concrete examples
- Better onboarding for new contributors
- Comprehensive reference for debugging and extending compiler

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: skeptomai