feat: add "hide whitespace changes" option for diffs

[ipanasenko]

Hey guys! First of all - I want to tell that I appreciate your work a lot ❤️
Theo's videos, T3 Code, advocating for open source - it's all amazing stuff.

I wanted to contribute this exact thing the moment T3 Code was open sourced, but saw "not accepting contributions" and decided not to.

I'm mostly using Codex App, but I'm trying T3 Code from time to time, curious how you guys improve it every day.
Surprisingly, no "hide whitespaces" feature yet.

I have to say, this is a huuge deal breaker for me, I love reviewing lesser chunks of code, and this is exactly what this feature is for.
Hope this will be useful not just for me, but for other too 🙏

This PR adds "Hide whitespace changes" to Settings and a toogle in diff sidebar:

Before/After

Hiding whitespace changes can dramatically simplify reviewing code.

Unified view

Split view

Note

Add "hide whitespace changes" toggle to diff panel and settings

• Adds a diffIgnoreWhitespace client setting (default true) that controls whether diffs suppress whitespace-only changes.
• The diff panel gains a toggle button (PilcrowIcon) that reads from and writes back to this setting, and passes ignoreWhitespace into the checkpoint diff query.
• diffCheckpoints in CheckpointStore.ts conditionally appends --ignore-all-space to the git diff command when ignoreWhitespace is true.
• ignoreWhitespace is propagated through the full call chain: contracts → React Query helpers (included in cache key) → getTurnDiff/getFullThreadDiff → diffCheckpoints.
• Behavioral Change: whitespace changes are hidden by default in all new diffs; callers that don't pass ignoreWhitespace now get true via the ?? true default in CheckpointDiffQuery.ts. CheckpointReactor explicitly passes false to preserve existing behavior.

^{Macroscope summarized 27d3b21.}

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Note

Medium Risk
Medium risk because it changes the diff generation contract end-to-end (web query keys/RPC inputs through server git diff invocation), which could affect diff caching and checkpoint diff outputs across clients.

Overview
Adds a new “hide whitespace changes” capability for turn/thread diffs, controlled by a persisted client setting (diffIgnoreWhitespace, defaulting to true) and a DiffPanel toolbar toggle.

Threads the new ignoreWhitespace flag through the diff pipeline (contracts, React Query request + cache keys, server CheckpointDiffQuery, and CheckpointStore.diffCheckpoints), and implements it by conditionally adding git diff --ignore-all-space. Tests are updated/added to assert default behavior and that caches don’t collide across whitespace modes.

^{Reviewed by Cursor Bugbot for commit 27d3b21. Bugbot is set up for automated code reviews on this repo. Configure here.}

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[macroscopeapp]

Approvability

Verdict: Approved

This PR adds a straightforward user preference for hiding whitespace changes in diffs. The change is well-scoped, includes comprehensive tests, and only affects diff display formatting. Review comments have been addressed.

^{You can customize Macroscope's approvability policy. Learn more.}

[juliusmarminge]

default true pls.

[juliusmarminge]

true by default plsss

Suggested change

	diffIgnoreWhitespace: Schema.Boolean.pipe(Schema.withDecodingDefault(Effect.succeed(false))),
	diffIgnoreWhitespace: Schema.Boolean.pipe(Schema.withDecodingDefault(Effect.succeed(true))),

[ipanasenko]

Yeah, I also like it true by all the way, decided to keep current behaviour. Same as GitHub.

Pushed default true

[juliusmarminge]

Suggested change

	const ignoreWhitespace = input.ignoreWhitespace ?? false;
	const ignoreWhitespace = input.ignoreWhitespace ?? true;

[juliusmarminge]

Suggested change

	ignoreWhitespace: false,
	ignoreWhitespace: true,

Dismissing prior approval to re-evaluate a1c2eaf