Add documentation

[SmachuloTetiana]

Summary by CodeRabbit

• Documentation
  • Added comprehensive project documentation file containing project overview with feature listings, high-level structure diagram, quick start installation instructions, development prerequisites and setup commands, yarn scripts reference guide, architecture and tooling descriptions, dependency breakdown, contribution guidelines, links to external documentation and APIs, and support information.

[coderabbitai]

📝 Walkthrough

Walkthrough

A new PROJECT_DOCUMENTATION.md file is added to Excalidraw, providing a comprehensive project overview including features, quick start guide, development prerequisites, architecture details, yarn scripts reference, contribution steps, and organizational information.

Changes

Cohort / File(s)	Summary
Documentation PROJECT_DOCUMENTATION.md	New file added with comprehensive project documentation covering features, quick start instructions, development setup, architecture overview, yarn scripts table, contribution guidelines, and organizational/support information.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

Poem

A document so grand, with care and with thought,
Quick starts and setup, all neatly wrought!
From features to architecture, clear as can be,
Now developers know where to start—hooray for thee! 🐰📚

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 inconclusive)

Check name	Status	Explanation	Resolution
Title check	❓ Inconclusive	The title 'Add documentation' is vague and generic, failing to specify which documentation was added or what aspect of the project it covers.	Consider a more specific title such as 'Add PROJECT_DOCUMENTATION.md with project overview and setup guide' to clearly indicate the scope of the documentation being added.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@PROJECT_DOCUMENTATION.md`:
- Around line 42-56: The fenced code block containing the repository tree
diagram (the triple-backtick block with the packages/ ├── excalidraw/ ...
scripts/ listing) is missing a language identifier; add "text" immediately after
the opening ``` so the block becomes ```text to satisfy markdownlint MD040 and
preserve the diagram formatting.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: ee7c953d-1829-4e3e-b3c3-aa5fe18c33bf

📥 Commits

Reviewing files that changed from the base of the PR and between be47f1d and 4feba63.

📒 Files selected for processing (1)

• PROJECT_DOCUMENTATION.md

[coderabbitai]

⚠️ Potential issue | 🟡 Minor

Add a language identifier to the fenced block (markdownlint MD040).

At Line 42, the code fence is missing a language, which will trip markdownlint. Use text for the tree diagram.

🛠️ Proposed fix

-```
+```text
 packages/
 ├── excalidraw/     # `@excalidraw/excalidraw` - Main React component (npm package)
 ├── common/         # `@excalidraw/common` - Shared utilities and constants
 ├── element/        # `@excalidraw/element` - Element manipulation logic
 ├── math/           # `@excalidraw/math` - Math utilities and types
 └── utils/          # `@excalidraw/utils` - Export utilities

 excalidraw-app/     # Production app (excalidraw.com)
 examples/
 ├── with-nextjs/    # Next.js integration example
 └── with-script-in-browser/  # Browser script example
 dev-docs/           # Documentation site (Docusaurus)
 scripts/            # Build and release scripts

</details>

<details>
<summary>🧰 Tools</summary>

<details>
<summary>🪛 markdownlint-cli2 (0.22.0)</summary>

[warning] 42-42: Fenced code blocks should have a language specified

(MD040, fenced-code-language)

</details>

</details>

<details>
<summary>🤖 Prompt for AI Agents</summary>

Verify each finding against the current code and only fix it if needed.

In @PROJECT_DOCUMENTATION.md around lines 42 - 56, The fenced code block
containing the repository tree diagram (the triple-backtick block with the
packages/ ├── excalidraw/ ... scripts/ listing) is missing a language
identifier; add "text" immediately after the opening ``` so the block becomes