ktsu merge: implement batch configuration CRUD (closes #2)

[matt-edmondson]

Sub-task A of #15.

Note: my original draft of this issue said "closes #2." That was wrong — #2 was already resolved on 2026-05-03 by removing the dead --batch flag rather than wiring it up. This issue re-adds the flag with real CRUD semantics, as called out in #15.

MergeCommand today (KtsuTools/Commands/MergeCommand.cs) takes only <directory> and <filename> positional args. BlastMerge supported saving named batches of merge inputs and re-running them; this issue ports that functionality.

Surface

A "batch" is a saved bundle of merge inputs — at minimum the directory + filename pattern, optionally the diff style flag from sub-task B (#37) once that lands. Subcommand shape:

ktsu merge batch save <name> <directory> <filename> [--diff-style <style>]
ktsu merge batch list
ktsu merge batch show <name>
ktsu merge batch delete <name>
ktsu merge --batch <name>     # runs a saved batch

The existing positional form ktsu merge <directory> <filename> keeps working. --batch <name> re-introduces the option and is mutually exclusive with the positional args.

Storage

Use the existing settings infrastructure at KtsuTools.Core/Services/Settings/. ISettingsService.LoadOrCreate<T>() is generic over AppData<T>. Add a new MergeBatchSettings : AppData<MergeBatchSettings> with a Dictionary<string, MergeBatchEntry>. Don't roll a new persistence layer.

Tests

• Round-trip: save → list → show → delete.
• --batch <unknown> → exit non-zero with a clear message.
• Mutual-exclusion error when both --batch and positional args are passed.
• A saved batch with a --diff-style value survives a load (only meaningful once ktsu merge: add --diff-style flag (git unified vs side-by-side) #37 is in; until then accept the field but ignore on dispatch).

Out of scope

• Pre-baked templates (Common Repository Files, Repository Sync Batch). Users save their own.
• Importing/exporting batches. File separately if needed.

[matt-edmondson]

Done in 6540d64 (and the --diff-style half landed via PR #40 in 1434cc8).

Surface as shipped:

• ktsu merge-batch save <name> <directory> <filename> [--diff-style <style>]
• ktsu merge-batch list
• ktsu merge-batch show <name>
• ktsu merge-batch delete <name>
• ktsu merge --batch <name> runs a saved batch; respects the batch's persisted DiffStyle.

Persistence via MergeBatchSettings : AppData<MergeBatchSettings>. Tests in MergeBatchServiceTests.

Deviation from spec: CLI uses a top-level merge-batch branch rather than merge batch <verb> — Spectre.Console.Cli doesn't easily allow a default command (merge <dir> <file>) on a branch alongside subcommands. Storage shape is unchanged either way, so the CLI shape can be revisited without a data migration.

Closing.

---

Generated by Claude Code