Git blobs were always decoded as UTF-8, so files in GBK or other legacy encodings showed every line as changed in the gutter, diff, blame and commit views, and staging/committing could re-encode them wrongly.
Blob text is now decoded and encoded with the file's encoding: the open document's encoding, else detection on the working file with the project default as fallback, else detection on the blob. Covers line hunks, file-at-revision, blame, stage patch/hunks, commit, conflict versions, diff text, and the agent worktree's file_at, partial commit and patch helpers. Text that cannot be represented in the target encoding is reported as an error instead of being written lossily.
Fixes#243
未在 Windows 实机验证。