chore: update formatting penalties in .clang-format and clean up .gitignore; remove outdated testing and validation sections from developer guide

Signed-off-by: szdytom <szdytom@qq.com>

.clang-format

@@ -92,7 +92,7 @@ MacroBlockBegin: ''
 MacroBlockEnd:   ''
 MaxEmptyLinesToKeep: 1
 NamespaceIndentation: None
-PenaltyBreakAssignment: 2
+PenaltyBreakAssignment: 500
 PenaltyBreakBeforeFirstCallParameter: 1
 PenaltyBreakComment: 300
 PenaltyBreakFirstLessLess: 120
@@ -101,7 +101,7 @@ PenaltyBreakString: 1000
 PenaltyBreakTemplateDeclaration: 10
 PenaltyExcessCharacter: 1000000
 PenaltyReturnTypeOnItsOwnLine: 200
-PenaltyIndentedWhitespace: 0
+PenaltyIndentedWhitespace: 1
 PointerAlignment: Right
 PPIndentWidth:   -1
 ReferenceAlignment: Pointer

.gitignore

@@ -1,3 +1,4 @@
+.cache/
 .vscode/
 build/
 *.out

tilemap/docs/dev.md

@@ -166,44 +166,3 @@ void TerrainGenerator::my_custom_pass(TileMap &tilemap) {
     }
 }
 ```
-
-## Testing and Validation
-
-### Determinism Testing
-
-Verify same seed produces identical output across runs:
-```cpp
-auto seed = Seed::from_string("test");
-TileMap map1(4), map2(4);
-map_generate(map1, {seed});
-map_generate(map2, {seed});
-// Verify map1 == map2
-```
-
-### Distribution Analysis
-
-Check terrain type distributions match biome properties:
-- Count tile types per biome
-- Verify ratios within acceptable tolerance
-- Test with multiple seeds for statistical significance
-
-### Visual Validation
-
-Export maps to image formats for visual inspection:
-- Check for realistic terrain patterns
-- Verify biome transitions look natural
-- Ensure no artifacts from generation passes
-
-## Future Extensions
-
-### Potential Improvements
-
-- **Surface Feature Generation**: Trees, structures, resources
-- **Elevation System**: Height maps for 3D terrain
-- **River Generation**: Connected water systems
-- **Chunk Streaming**: Dynamic loading for large worlds
-- **Multithreading**: Parallel chunk generation
-
-### API Stability
-
-Core interfaces (TileMap, Chunk, Tile) are stable. Generation system is designed for extensibility without breaking existing code.