docs: rewrite README, add CLAUDE.md, refresh CONTRIBUTING

[patrikbraborec]

Summary

• Rewrites README.md around a scannable structure (one-line description, features, 3-step quick start, per-platform install, commands table, docs links, telemetry, contributing, support, license) aimed at both users and AI agents. Moves the .actor/actor.json deep dive and env-vars reference out to the platform docs.
• Adds a root CLAUDE.md with project overview, key directories, common commands, a pre-push checklist (yarn lint → yarn format → yarn build → yarn test:local), test hook patterns, and release flow.
• Refreshes CONTRIBUTING.md: adds prerequisites, local setup, code style tooling (Biome / ESLint / Prettier), test categories table, PR guidelines, and rewrites the Publish section to match the actual automated release flow (no more manual package.json bump).

Closes #1067

Test plan

• yarn lint passes
• yarn format passes (Prettier on the three Markdown files)
• yarn build succeeds
• Review rendered Markdown on GitHub
• Sanity-check links (docs.apify.com, console.apify.com, Discord) resolve

🤖 Generated with Claude Code

[l2ysho]

CLAUDE.md is generated with /init? It is very verbose, in general it is good to keep it as short as possible, do not put there something which claude can find out by simply looking to codebase. Things to avoid part is valuable though.

I tried to "destile" this one using claude, but feel free to discuss this with someone more competent than me. (maybe I am too strict buy i think this is still too long :] )

# CLAUDE.md
                                                                                                                                                                                                  
  Guidance for Claude Code working in this repository. Humans should read [README.md](./README.md) and [CONTRIBUTING.md](./CONTRIBUTING.md) first.                                                
                                                                                                                                                                                                  
  ## Entry points                                                                                                                                                                                 
                                                                                                       
  - `apify` CLI — `src/entrypoints/apify.ts`                                                                                                                                                      
  - `actor` CLI — `src/entrypoints/actor.ts`
                                                                                                                                                                                                  
  ## Before you push                                                                                   
                                                                                                                                                                                                  
  Run `yarn lint && yarn format && yarn build && yarn test:local` before pushing. Run `yarn test:api` too if you changed anything that touches the Apify API.                                     
          
  If you modified a command's flags, args, description, or added/removed a command, also run `yarn update-docs` and commit the regenerated `docs/` output.                                        
                                                                                                       
  ## Code conventions                                                                                                                                                                             
                                                                                                       
  - Package manager: **Yarn 4** (via Corepack). Do not use npm.                                                                                                                                   
  - Use `.js` import specifiers for local files (e.g. `import { foo } from './foo.js'`). The `.ts` source resolves at build time.
  - Commands extend `ApifyCommand` from `src/lib/command-framework/apify-command.ts`. Follow the pattern of existing commands: `static override name`, `static override description`, `static     
  override flags/args`, and an `async run()` method.                                                                                                                                              
  - New commands must be registered in `src/commands/_register.ts` (or the parent `_index.ts` for subcommands).                                                                                   
  - Do not add docstrings, comments, or type annotations to code you did not change. Keep diffs tight.                                                                                            
                                                                                                                                                                                                  
  ## Testing                                                                                                                                                                                      
                                                                                                                                                                                                  
  - Tests use **Vitest**. See [CONTRIBUTING.md](./CONTRIBUTING.md#writing-tests) for `useAuthSetup` and `useTempPath` hook usage.                                                                 
  - API tests must include `[api]` in the test name and live in `test/api/`.
  - Always `import process from 'node:process'` in command/lib code — never use `globalThis.process`. This is required for test cwd mocks to work.                                                
                                                                                                                                                                                                  
  ## Things to avoid
                                                                                                                                                                                                  
  - Do not use `--no-verify` to skip git hooks. Fix the underlying issue.                                                                                                                         
  - Do not edit `docs/` by hand — it is generated by `yarn update-docs`.

[patrikbraborec]

@l2ysho yeah, it was /init. Thanks for the correction, I will update it! Let's keep it short, and iterate.