Feature: Git Remote Storage via Apex

## Summary

Add support for using Apex as a Git remote backend by storing Git objects in Celestia blobs.

Example usage:

```
git clone celestia://repo
git push celestia://repo
```

## Motivation

Git uses content-addressed storage where objects are identified by hashes. This maps well to Celestia blob storage.

Benefits:

- Immutable repository history
- Decentralized hosting
- Deduplication of identical objects
- Globally verifiable repository state

## Architecture

```
Git client
↓
Git remote service
↓
Apex blob client
↓
Celestia blobs
```

SQLite can act as a local index/cache mapping Git object hashes to blob references.

## Possible Implementation

**Option A:** Implement a custom git remote helper:

```
git-remote-apex
```

**Option B:** Implement Git smart HTTP support via an Apex HTTP gateway.