feat(cli): show the change, the reasoning, and the whole error

[oratis]

Finding A from docs/THREE_WAY_REVIEW.md — the CLI presentation layer. The REPL printed a tool call as one line, its result cut at 200 characters, no colour anywhere, and dropped every reasoning token the model produced. Approving an Edit meant answering y/n to a tool name.

What changes

Diffs. Edit and Write render a hunked, capped unified diff — at the approval prompt, and again when the call runs, so acceptEdits (which has no prompt) still shows the change. Write is diffed against the file on disk when one exists, so an overwrite doesn't read as a creation. Bash prints its command in full, every line.

  ● Edit  src/auth.ts
       1   function login(user) {
       2 +   if (!user) throw new Error("no user");
       3     return db.find(user);
       4   }

Long files collapse: a two-line change in a 900-line file prints as ~6 rows with ⋯ markers, and a whole-file rewrite caps with ⋯ N more changed lines.

Reasoning. thinking_delta went straight to return. It now streams into a dim gutter that closes before anything else prints. DeepSeek's reasoner is the premise of this product and its reasoning was the one thing the terminal threw away. --no-thinking opts out.

Output. Tool results elide the middle instead of cutting at 200 bytes — the tail of a failing command is usually the part that matters. Single pathological lines (minified JSON, base64) are clipped so they can't flood the terminal.

Colour. Resolved once at startup from --no-color, NO_COLOR, FORCE_COLOR, TERM=dumb, and whether stdout is a TTY, then threaded through as a palette — piped output is byte-identical minus the escapes.

Shared differ

apps/desktop/src/lib/diff.ts moves into packages/core/src/util/diff.ts; the desktop module re-exports it. The file panel and the terminal now render diffs from one implementation instead of two.

Review notes

Two bugs came out of rendering real output rather than trusting green tests, both now covered:

• reasoning was painted per character — ESC[2mT ESC[0m ESC[2mh ESC[0m …, kilobytes of escape soup for one paragraph
• a failing command's elision marker was painted twice (ESC[31m ESC[2m … ESC[0m ESC[0m)

render.ts is pure string → string, so all of it is tested without a TTY: 29 new cases covering colour precedence, diff hunking/capping, elision, approval previews per tool, and the reasoning stream's line-state machine.

Verification

pnpm typecheck · lint · format:check clean. core 718/16 skipped · cli 204 · desktop 54 · server 41 · protocol 24 · vscode 12 · lsp 13 · scripts 21. Rendered sample output through the built module and read the raw bytes with cat -v — that is how both colour bugs surfaced.

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