fix: threading macros, REPL stability, and CI coverage

- fix(emitter): emitFnWrapper now uses runtimeName for builtin operators
- fix(emitter): map/reduce handlers support variadic runtime functions (+, -, etc.)
- fix(emitter): variadic runtime functions list extracted to variadicRuntimeFns constant
- fix(macros): restore correct thread-first behavior (->) and fix result shadowing
- fix(macros): and/or/as->/some->/some->> macro result variable fixes
- fix(repl): add macroexpand step before interpreter eval
- fix(runtime): cljReduceSeq handles nil init (uses first coll element)
- fix(eval): add macroexpand/macroexpand-1 special forms to interpreter
- fix(eval): add macros module import for macroexpand access
- fix(warnings): eliminate ResultShadowed and UnusedImport warnings
- chore(.gitignore): remove artifact entries (-o, =0.4.0), unignore lib/bring_http.nim
- chore(ci): run all examples + threading macro + macroexpand REPL smoke tests

.gitignore

@@ -17,8 +17,6 @@ test_ai_assist
 
 
 # Artifacts / temp files
--o
-=0.4.0
 __pycache__/
 test_single_debug.py
 
@@ -26,4 +24,3 @@ test_single_debug.py
 src/tui_config
 experiments/native-lib/test_client/test_client
 experiments/wasm/tools/zig/
-lib/bring_http.nim