Implements Phase 2 (Language Frontend) of the Ephapax roadmap:

- ephapax-lexer: High-performance lexer using logos
  - Tokenizes all Ephapax syntax (keywords, operators, literals)
  - Support for nested block comments {- -}
  - String escape sequence handling
  - Comprehensive error recovery
  - 20+ unit tests

- ephapax-parser: Parser combinator implementation using chumsky
  - Complete expression parsing (let, fn, if, region, case, etc.)
  - Type parsing (base types, String@region, functions, products, sums)
  - Declaration parsing (fn, type)
  - Rich error reporting with ariadne
  - 19 unit tests + doc tests

All tests pass successfully.

- Complete ephapax-typing with full expression type checking
  (pair, sum types, case, let, string operations)
- Add ephapax-interp tree-walking interpreter for debugging
- Create ephapax-repl with interactive REPL and commands
  (:help, :type, :load, :tokens, :reset, :verbose)
- Build ephapax-cli with subcommands (run, check, compile, repl)
- Add ephapax-stdlib with prelude, I/O, string, math modules
- Add compile_module function to ephapax-wasm

Set up directory structure for Ephapax libraries:
- library/common/ for shared language implementations
- library/specific/ for Ephapax-specific code

Common Library (from aggregate-library):
- arithmetic: add, subtract, multiply, divide, modulo
- comparison: less_than, greater_than, equal, not_equal, etc.
- logical: and, or, not
- string: concat, length, substring
- collection: map, filter, fold, contains
- conditional: if_then_else

Ephapax-Specific Library:
- linear: move, drop, copy (linear type operations)
- region: new_region, alloc_in (region-based memory)
- memory: borrow (reference operations)
- wasm: compile_to_wasm (WebAssembly compilation)

Renamed library/ to aggregate-library/ with clearer structure:

Common Library (22 ops from hyperpolymath/aggregate-library):
- arithmetic: add, subtract, multiply, divide, modulo
- comparison: equal, not_equal, less_than, greater_than, less_equal, greater_equal
- logical: and, or, not
- string: concat, length, substring
- collection: map, filter, fold, contains
- conditional: if_then_else

Ephapax-Specific Library (17 ops):
- linear: move, drop, copy, borrow
- region: new_region, alloc_in
- io: print, println, read_line
- conversion: i32_to_string, string_to_i32
- product: pair, fst, snd
- sum: inl, inr, case

Total: 39 fully-specified operations