feat: support freeze pane via @FreezePane or register WriteHandler on write

[bengbengbalabalabeng]

Purpose of the pull request

Closed: #913

What's changed?

Added excel sheet freeze pane support.

Use Case:

• Freeze columns 1-2 (A-B) and row 1 in the sheet.

// for bean annotation
@FreezePane(colSplit = 2, rowSplit = 1)
public class Model { ... }

FesodSheet.write(file, Model.class)
      .sheet()
      .doWrite(data);

// for write-handler
FesodSheet.write(file)
      .registerWriteHandler(new SheetFreezePaneStrategy(2, 1, 2, 1))
      .sheet()
      .doWrite(data);

• Freeze rows 1–3 and columns 1–2 (A-B) in the sheet. The right pane starts displaying from column 6 (F) by default, and the bottom pane starts displaying from row 11 by default.

// for bean annotation
@FreezePane(colSplit = 2, rowSplit = 3, leftmostColumn = 5, topRow = 10)
public class Model { ... }

FesodSheet.write(file, Model.class)
      .sheet()
      .doWrite(data);

// for write-handler
FesodSheet.write(file)
      .registerWriteHandler(new SheetFreezePaneStrategy(2, 3, 5, 10))
      .sheet()
      .doWrite(data);

Checklist

• I have read the Contributor Guide.
• I have written the necessary doc or comment.
• I have added the necessary unit tests and all cases have passed.

[Copilot]

Pull request overview

This PR adds Excel sheet freeze pane support to Fesod’s write pipeline, enabling freeze panes to be configured either declaratively via a new @FreezePane class annotation or imperatively via a new SheetFreezePaneStrategy write handler (Closes #913).

Changes:

• Introduces @FreezePane plus SheetFreezePaneProperty to model freeze pane configuration derived from the head class.
• Adds SheetFreezePaneStrategy (a SheetWriteHandler) and wires it into annotation-driven handler initialization.
• Adds unit/integration tests to validate property building and end-to-end freeze pane behavior for both .xlsx and .xls.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
fesod-sheet/src/main/java/org/apache/fesod/sheet/annotation/write/style/FreezePane.java	New annotation to declare freeze pane configuration on the head model class.
fesod-sheet/src/main/java/org/apache/fesod/sheet/metadata/property/SheetFreezePaneProperty.java	New property object to map @FreezePane values into a runtime configuration.
fesod-sheet/src/main/java/org/apache/fesod/sheet/write/style/SheetFreezePaneStrategy.java	New SheetWriteHandler that applies Sheet#createFreezePane(...) after sheet creation.
fesod-sheet/src/main/java/org/apache/fesod/sheet/write/property/ExcelWriteHeadProperty.java	Captures @FreezePane into ExcelWriteHeadProperty for downstream handler setup.
fesod-sheet/src/main/java/org/apache/fesod/sheet/write/metadata/holder/AbstractWriteHolder.java	Registers SheetFreezePaneStrategy when @FreezePane is present on the head class.
fesod-sheet/src/test/java/org/apache/fesod/sheet/metadata/property/SheetFreezePanePropertyTest.java	Tests annotation-to-property mapping and defaulting behavior.
fesod-sheet/src/test/java/org/apache/fesod/sheet/write/style/SheetFreezePaneStrategyTest.java	Tests strategy validation and that it delegates to Sheet#createFreezePane(...).
fesod-sheet/src/test/java/org/apache/fesod/sheet/write/freezepane/SheetFreezePaneTest.java	End-to-end tests that confirm freeze panes are present/absent in generated workbooks.

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