Docs/add grok build cli to readme

[boredcity]

Who is submitting this PR? (required)

Human person through and through, wanted to make sure I get it right and test it :)

What problem are you trying to solve?

There was no documented way to use this with Grok Build CLI, I documented one.

What does this PR change?

Grok Build CLI section to README.md file + link to it in the same file

Is this change appropriate for the core library?

Yes, it's a readme change intended for user-facing surface

What alternatives did you consider?

Being sad and having worse docs. Decided to go with better docs :)

Does this PR contain multiple unrelated changes?

No

Existing PRs

• I have reviewed all open AND closed PRs for duplicates or prior art
• Related PRs: none found

Environment tested

Tested commands with version [stable]

Harness (e.g. Claude Code, Cursor)	Harness version	Model	Model version/ID
Grok Build CLI	0.2.82 (6d0b07d2de0f)	Grok Build	0.1
Grok Build CLI	0.2.82 (6d0b07d2de0f)	Composer	2.5

New harness support (required if this PR adds a new harness)

Clean-session transcript for "Let's make a react todo list"

     ❯ Let's make a react todo list                                                                                                                                                                        11:43 AM


     ◆ Thought for 0.7s

     I'll start by checking the workspace and the relevant skills for building a React todo list.                                                                                                          11:43 AM

     ◆ Skill using-superpowers
     ◆ Search "**/*" (no matches)
     ◆ Skill brainstorming
     ◆ Skill modern-web-guidance
     ◆ Thought for 1.8s

     Using the brainstorming skill to shape the design before we write any code. The workspace is empty, so this is a greenfield React app.                                                                11:43 AM

     ◆ Thought for 0.0s
 ┌                                                                                                                                                                                                                   ┐
 │   The workspace is empty, so we're starting from scratch. Before I scaffold anything, I want to nail down what you're building.                                                                         11:43 AM  │
 │                                                                                                                                                                                                                   │
 │   What level of features do you want?                                                                                                                                                                             │
 │                                                                                                                                                                                                                   │
 │   • A) Classic — add, mark complete, delete                                                                                                                                                                       │
 │   • B) Standard — classic + filter (all/active/done) + clear completed                                                                                                                                            │
 │   • C) Full — standard + localStorage persistence + edit inline                                                                                                                                                   │
 │                                                                                                                                                                                                                   │
 │   Which fits best? (Or describe something different.)                                                                                                                                                             │
 └                                                                                                                                                                                                                   ┘
     Turn completed in 14s.

Evaluation

I added couple of lines in readme carefully testing them in terminal. 🤷‍♂️
Verified link worked with markdown previewer.

Rigor

• This change was tested adversarially, not just on the happy path
• I did not modify carefully-tuned content (Red Flags table,
  rationalizations, "human partner" language) without extensive evals
  showing the change is an improvement

Human review

• A human has reviewed the COMPLETE proposed diff before submission

[boredcity]

Oops, started with main and brought some changes from there it seems? 👀 will just leave my stuff.

upd: no actual changes done by mode but it cherry-picked my commit on top of dev branch; because who likes doing this stuff manually.