chore: 引入仓库根 .clang-format 与 .gitignore

平衡板从 firmware 主仓拆出后，作为独立产品需要自己的代码风格和忽略规则。
.clang-format 沿用主仓 projects/.clang-format 的全套约定（C++/Zephyr 风格），
保证拆出前后 reformat 结果一致；.gitignore 在主仓基础上裁剪掉 Android、
Unity 相关条目，仅保留嵌入式构建产物、IDE 本地配置和 OS 临时文件。

.clang-format

@@ -0,0 +1,320 @@
+---
+Language:        Cpp
+AlignAfterOpenBracket: true
+AccessModifierOffset: -2
+AlignArrayOfStructures: None
+AlignConsecutiveAssignments:
+  Enabled:         true
+  AcrossEmptyLines: false
+  AcrossComments:  false
+  AlignCompound:   false
+  AlignFunctionDeclarations: false
+  AlignFunctionPointers: false
+  PadOperators:    true
+AlignConsecutiveBitFields:
+  Enabled:         false
+  AcrossEmptyLines: false
+  AcrossComments:  false
+  AlignCompound:   false
+  AlignFunctionDeclarations: false
+  AlignFunctionPointers: false
+  PadOperators:    false
+AlignConsecutiveDeclarations:
+  Enabled:         false
+  AcrossEmptyLines: false
+  AcrossComments:  false
+  AlignCompound:   false
+  AlignFunctionDeclarations: true
+  AlignFunctionPointers: false
+  PadOperators:    false
+AlignConsecutiveMacros:
+  Enabled:         true
+  AcrossEmptyLines: false
+  AcrossComments:  false
+  AlignCompound:   false
+  AlignFunctionDeclarations: false
+  AlignFunctionPointers: false
+  PadOperators:    false
+AlignConsecutiveShortCaseStatements:
+  Enabled:         false
+  AcrossEmptyLines: false
+  AcrossComments:  false
+  AlignCaseArrows: false
+  AlignCaseColons: false
+AlignConsecutiveTableGenBreakingDAGArgColons:
+  Enabled:         false
+  AcrossEmptyLines: false
+  AcrossComments:  false
+  AlignCompound:   false
+  AlignFunctionDeclarations: false
+  AlignFunctionPointers: false
+  PadOperators:    false
+AlignConsecutiveTableGenCondOperatorColons:
+  Enabled:         false
+  AcrossEmptyLines: false
+  AcrossComments:  false
+  AlignCompound:   false
+  AlignFunctionDeclarations: false
+  AlignFunctionPointers: false
+  PadOperators:    false
+AlignConsecutiveTableGenDefinitionColons:
+  Enabled:         false
+  AcrossEmptyLines: false
+  AcrossComments:  false
+  AlignCompound:   false
+  AlignFunctionDeclarations: false
+  AlignFunctionPointers: false
+  PadOperators:    false
+AlignEscapedNewlines: Right
+AlignOperands:   Align
+AlignTrailingComments:
+  AlignPPAndNotPP: true
+  Kind:            Always
+  OverEmptyLines:  0
+AllowAllArgumentsOnNextLine: true
+AllowAllParametersOfDeclarationOnNextLine: false
+AllowBreakBeforeNoexceptSpecifier: Never
+AllowBreakBeforeQtProperty: false
+AllowShortBlocksOnASingleLine: Never
+AllowShortCaseExpressionOnASingleLine: true
+AllowShortCaseLabelsOnASingleLine: false
+AllowShortCompoundRequirementOnASingleLine: true
+AllowShortEnumsOnASingleLine: false
+AllowShortFunctionsOnASingleLine: None
+AllowShortIfStatementsOnASingleLine: WithoutElse
+AllowShortLambdasOnASingleLine: All
+AllowShortLoopsOnASingleLine: false
+AllowShortNamespacesOnASingleLine: false
+AlwaysBreakAfterDefinitionReturnType: None
+AlwaysBreakBeforeMultilineStrings: false
+AttributeMacros:
+  - __capability
+BinPackArguments: true
+BinPackLongBracedList: true
+BinPackParameters: OnePerLine
+BitFieldColonSpacing: Both
+BracedInitializerIndentWidth: -1
+BraceWrapping:
+  AfterCaseLabel:  false
+  AfterClass:      true
+  AfterControlStatement: Never
+  AfterEnum:       false
+  AfterExternBlock: true
+  AfterFunction:   false
+  AfterNamespace:  true
+  AfterObjCDeclaration: true
+  AfterStruct:     false
+  AfterUnion:      false
+  BeforeCatch:     true
+  BeforeElse:      false
+  BeforeLambdaBody: false
+  BeforeWhile:     false
+  IndentBraces:    false
+  SplitEmptyFunction: true
+  SplitEmptyRecord: true
+  SplitEmptyNamespace: true
+BreakAdjacentStringLiterals: true
+BreakAfterAttributes: Leave
+BreakAfterJavaFieldAnnotations: false
+BreakAfterOpenBracketBracedList: false
+BreakAfterOpenBracketFunction: true
+BreakAfterOpenBracketIf: false
+BreakAfterOpenBracketLoop: false
+BreakAfterOpenBracketSwitch: false
+BreakAfterReturnType: None
+BreakArrays:     true
+BreakBeforeBinaryOperators: None
+BreakBeforeCloseBracketBracedList: false
+BreakBeforeCloseBracketFunction: false
+BreakBeforeCloseBracketIf: false
+BreakBeforeCloseBracketLoop: false
+BreakBeforeCloseBracketSwitch: false
+BreakBeforeConceptDeclarations: Always
+BreakBeforeBraces: Custom
+BreakBeforeInlineASMColon: OnlyMultiline
+BreakBeforeTemplateCloser: false
+BreakBeforeTernaryOperators: true
+BreakBinaryOperations: Never
+BreakConstructorInitializers: BeforeColon
+BreakFunctionDefinitionParameters: false
+BreakInheritanceList: BeforeColon
+BreakStringLiterals: true
+BreakTemplateDeclarations: MultiLine
+ColumnLimit:     120
+CommentPragmas:  '^ IWYU pragma:'
+CompactNamespaces: false
+ConstructorInitializerIndentWidth: 4
+ContinuationIndentWidth: 4
+Cpp11BracedListStyle: Block
+DerivePointerAlignment: false
+DisableFormat:   false
+EmptyLineAfterAccessModifier: Never
+EmptyLineBeforeAccessModifier: LogicalBlock
+EnumTrailingComma: Leave
+ExperimentalAutoDetectBinPacking: false
+FixNamespaceComments: true
+ForEachMacros:
+  - foreach
+  - Q_FOREACH
+  - BOOST_FOREACH
+IfMacros:
+  - KJ_IF_MAYBE
+IncludeBlocks:   Preserve
+IncludeCategories:
+  - Regex:           '^"(llvm|llvm-c|clang|clang-c)/'
+    Priority:        2
+    SortPriority:    0
+    CaseSensitive:   false
+  - Regex:           '^(<|"(gtest|gmock|isl|json)/)'
+    Priority:        3
+    SortPriority:    0
+    CaseSensitive:   false
+  - Regex:           '.*'
+    Priority:        1
+    SortPriority:    0
+    CaseSensitive:   false
+IncludeIsMainRegex: '(Test)?$'
+IncludeIsMainSourceRegex: ''
+IndentAccessModifiers: false
+IndentCaseBlocks: false
+IndentCaseLabels: false
+IndentExportBlock: true
+IndentExternBlock: AfterExternBlock
+IndentGotoLabels: true
+IndentPPDirectives: None
+IndentRequiresClause: true
+IndentWidth:     4
+IndentWrappedFunctionNames: false
+InsertBraces:    false
+InsertNewlineAtEOF: false
+InsertTrailingCommas: None
+IntegerLiteralSeparator:
+  Binary:          0
+  BinaryMinDigitsInsert: 0
+  BinaryMaxDigitsRemove: 0
+  Decimal:         0
+  DecimalMinDigitsInsert: 0
+  DecimalMaxDigitsRemove: 0
+  Hex:             0
+  HexMinDigitsInsert: 0
+  HexMaxDigitsRemove: 0
+  BinaryMinDigits: 0
+  DecimalMinDigits: 0
+  HexMinDigits:    0
+JavaScriptQuotes: Leave
+JavaScriptWrapImports: true
+KeepEmptyLines:
+  AtEndOfFile:     false
+  AtStartOfBlock:  true
+  AtStartOfFile:   true
+KeepFormFeed:    false
+LambdaBodyIndentation: Signature
+LineEnding:      DeriveLF
+MacroBlockBegin: ''
+MacroBlockEnd:   ''
+MainIncludeChar: Quote
+MaxEmptyLinesToKeep: 1
+NamespaceIndentation: None
+NumericLiteralCase:
+  ExponentLetter:  Leave
+  HexDigit:        Leave
+  Prefix:          Leave
+  Suffix:          Leave
+ObjCBinPackProtocolList: Auto
+ObjCBlockIndentWidth: 2
+ObjCBreakBeforeNestedBlockParam: true
+ObjCSpaceAfterProperty: false
+ObjCSpaceBeforeProtocolList: true
+OneLineFormatOffRegex: ''
+PackConstructorInitializers: BinPack
+PenaltyBreakAssignment: 2
+PenaltyBreakBeforeFirstCallParameter: 19
+PenaltyBreakBeforeMemberAccess: 150
+PenaltyBreakComment: 300
+PenaltyBreakFirstLessLess: 120
+PenaltyBreakOpenParenthesis: 0
+PenaltyBreakScopeResolution: 500
+PenaltyBreakString: 1000
+PenaltyBreakTemplateDeclaration: 10
+PenaltyExcessCharacter: 1000000
+PenaltyIndentedWhitespace: 0
+PenaltyReturnTypeOnItsOwnLine: 1000
+PointerAlignment: Right
+PPIndentWidth:   -1
+QualifierAlignment: Leave
+ReferenceAlignment: Pointer
+ReflowComments:  Always
+RemoveBracesLLVM: false
+RemoveEmptyLinesInUnwrappedLines: false
+RemoveParentheses: Leave
+RemoveSemicolon: false
+RequiresClausePosition: OwnLine
+RequiresExpressionIndentation: OuterScope
+SeparateDefinitionBlocks: Leave
+ShortNamespaceLines: 1
+SkipMacroDefinitionBody: false
+SortIncludes:
+  Enabled:         true
+  IgnoreCase:      false
+  IgnoreExtension: false
+SortJavaStaticImport: Before
+SortUsingDeclarations: LexicographicNumeric
+SpaceAfterCStyleCast: false
+SpaceAfterLogicalNot: false
+SpaceAfterOperatorKeyword: false
+SpaceAfterTemplateKeyword: true
+SpaceAroundPointerQualifiers: Default
+SpaceBeforeAssignmentOperators: true
+SpaceBeforeCaseColon: false
+SpaceBeforeCpp11BracedList: false
+SpaceBeforeCtorInitializerColon: true
+SpaceBeforeInheritanceColon: true
+SpaceBeforeJsonColon: false
+SpaceBeforeParens: ControlStatements
+SpaceBeforeParensOptions:
+  AfterControlStatements: true
+  AfterForeachMacros: true
+  AfterFunctionDefinitionName: false
+  AfterFunctionDeclarationName: false
+  AfterIfMacros:   true
+  AfterNot:        false
+  AfterOverloadedOperator: false
+  AfterPlacementOperator: true
+  AfterRequiresInClause: false
+  AfterRequiresInExpression: false
+  BeforeNonEmptyParentheses: false
+SpaceBeforeRangeBasedForLoopColon: true
+SpaceBeforeSquareBrackets: false
+SpaceInEmptyBraces: Never
+SpacesBeforeTrailingComments: 1
+SpacesInAngles:  Never
+SpacesInContainerLiterals: true
+SpacesInLineCommentPrefix:
+  Minimum:         1
+  Maximum:         -1
+SpacesInParens:  Never
+SpacesInParensOptions:
+  ExceptDoubleParentheses: false
+  InCStyleCasts:   false
+  InConditionalStatements: false
+  InEmptyParentheses: false
+  Other:           false
+SpacesInSquareBrackets: false
+Standard:        Latest
+StatementAttributeLikeMacros:
+  - Q_EMIT
+StatementMacros:
+  - Q_UNUSED
+  - QT_REQUIRE_VERSION
+TableGenBreakInsideDAGArg: DontBreak
+TabWidth:        4
+UseTab:          Never
+VerilogBreakBetweenInstancePorts: true
+WhitespaceSensitiveMacros:
+  - BOOST_PP_STRINGIZE
+  - CF_SWIFT_NAME
+  - NS_SWIFT_NAME
+  - PP_STRINGIZE
+  - STRINGIZE
+WrapNamespaceBodyWithEmptyLines: Leave
+...

.gitignore

@@ -1,6 +1,38 @@
-# editors
+# =========================================================
+# Editor swap / backup
+# =========================================================
 *.swp
 *~
 
-# build
+# =========================================================
+# IDE 本地配置
+# =========================================================
+.idea/
+*.iml
+.vscode/
+.codex
+.claude
+
+# =========================================================
+# Embedded / CMake / Zephyr 构建产物
+# =========================================================
 /build*/
+build/
+**/build/
+**/zephyr/
+**/output/
+*.o
+*.obj
+*.elf
+*.bin
+*.hex
+*.map
+*.ninja
+.ninja_deps
+.ninja_log
+
+# =========================================================
+# OS 临时文件
+# =========================================================
+.DS_Store
+Thumbs.db