refactor: Modularize codebase and separate implementation from headers

This commit restructures the project from a flat, header-heavy architecture into distinct modules (Core, Analysis, Synthesis, UI, Z3) and moves implementation logic into compiled source files.

- CMakeLists.txt:
  - Reorganize source files into module-specific groups
  - Update paths to reflect the new `src/<module>/` directory structure

- include/structor/*.hpp (modified):
  - Remove inline implementations from `access_collector.hpp`, `layout_synthesizer.hpp`, `structure_persistence.hpp`, and `type_propagator.hpp`
  - Reduce headers to pure declarations to minimize include bloat

- src/*/*.cpp (added):
  - Move implementation logic from headers to corresponding source files in `src/analysis/`, `src/synthesis/`, and `src/core/`
  - Remove `inline` keywords as functions are now compiled in translation units

- include/structor/core/fwd.hpp (added):
  - Introduce a central forward-declaration header to reduce circular dependencies and compile-time coupling

- include/structor/structor.hpp (added):
  - Add a master include header that aggregates the public API across all modules

Impact:
- Significantly improves incremental build times by breaking header dependencies.
- No functional changes to plugin behavior; this is a purely structural refactor.
- Establishes a clearer separation of concerns between analysis logic, Z3 integration, and UI code.

Author: 19h

CMakeLists.txt

@@ -232,17 +232,27 @@ include_directories(
     ${CMAKE_SOURCE_DIR}/include
 )
 
-# Source files
+# Source files - organized by module
 set(STRUCTOR_SOURCES
-    src/plugin.cpp
-    src/config.cpp
-    src/access_collector.cpp
-    src/layout_synthesizer.cpp
-    src/vtable_detector.cpp
-    src/type_propagator.cpp
-    src/pseudocode_rewriter.cpp
-    src/structure_persistence.cpp
-    src/ui_integration.cpp
+    # Core module
+    src/core/config.cpp
+    
+    # Analysis module
+    src/analysis/access_collector.cpp
+    src/analysis/cross_function_analyzer.cpp
+    src/analysis/vtable_detector.cpp
+    
+    # Synthesis module
+    src/synthesis/layout_synthesizer.cpp
+    src/synthesis/structure_persistence.cpp
+    src/synthesis/type_propagator.cpp
+    
+    # UI module
+    src/ui/plugin.cpp
+    src/ui/pseudocode_rewriter.cpp
+    src/ui/ui_integration.cpp
+    
+    # Z3 module
     src/z3/context.cpp
     src/z3/type_encoding.cpp
     src/z3/constraint_tracker.cpp
@@ -254,7 +264,6 @@ set(STRUCTOR_SOURCES
     src/z3/type_inference_engine.cpp
     src/z3/alias_analysis.cpp
     src/z3/type_applicator.cpp
-    src/cross_function_analyzer.cpp
 )
 
 set(STRUCTOR_HEADERS