docs: add bashkit homepage links (#1551)

## What
Add the bashkit.sh homepage link to the root README, Rust crate docs,
Python README, and Node.js README.

## Why
Make the canonical project homepage visible across package docs.

## How
Added a short `Homepage: [bashkit.sh](https://bashkit.sh)` line near the
top of each requested doc.

## Risk
- Low
- Docs-only change; package behavior is unchanged.

## Checklist
- [x] Tests added or updated
- [x] Backward compatibility considered

Validation:
- `just test`
- `just pre-pr`

Author: chaliy

README.md

@@ -8,6 +8,8 @@
 
 Awesomely fast virtual sandbox with bash and file system. Written in Rust.
 
+Homepage: [bashkit.sh](https://bashkit.sh)
+
 ## Features
 
 - **Secure by default** - No process spawning, no filesystem access, no network access unless explicitly enabled. [250+ threats](specs/threat-model.md) analyzed and mitigated

crates/bashkit-js/README.md

@@ -2,6 +2,8 @@
 
 Sandboxed bash interpreter for JavaScript and TypeScript. Native NAPI-RS bindings to the `bashkit` Rust core for Node.js, Bun, and Deno.
 
+Homepage: [bashkit.sh](https://bashkit.sh)
+
 ## Features
 
 - Sandboxed, in-process execution with a virtual filesystem

crates/bashkit-python/README.md

@@ -4,6 +4,8 @@
 
 Sandboxed bash interpreter for Python. Native bindings to the `bashkit` Rust core for fast, in-process execution with a virtual filesystem.
 
+Homepage: [bashkit.sh](https://bashkit.sh)
+
 ## Features
 
 - Sandboxed execution in-process, without containers or subprocess orchestration

crates/bashkit/src/lib.rs

@@ -3,6 +3,8 @@
 //! Virtual bash interpreter for AI agents, CI/CD pipelines, and code sandboxes.
 //! Written in Rust.
 //!
+//! Homepage: [bashkit.sh](https://bashkit.sh)
+//!
 //! # Features
 //!
 //! - **POSIX compliant** - Substantial IEEE 1003.1-2024 Shell Command Language compliance