Revert "fix(storage): address the DSN bucket through the endpoint and refuse a DSN that names no device"

[abnegate]

Reverts #246

[greptile-apps]

Greptile Summary

This PR reverts the preceding storage DSN validation and endpoint-addressing change, restoring local fallback for unusable DSNs and root-based S3 bucket handling.

• Restores the prior StorageFactory construction logic and associated unit tests.
• Relaxes and relocks utopia-php/storage to 4.0.0 with corresponding transitive dependency downgrades.
• Restores the earlier storage DSN documentation.

Confidence Score: 4/5

The PR should not merge until S3 bucket 0 is preserved rather than silently redirected to the root namespace.

The restored bucket normalization explicitly classifies the nonempty string 0 as absent, so valid DSNs for that bucket generate incorrect object paths.

Files Needing Attention: src/Executor/StorageFactory.php, tests/unit/Executor/StorageFactoryTest.php

Important Files Changed

Filename	Overview
src/Executor/StorageFactory.php	Restores fallback and S3 root construction but incorrectly discards the valid bucket name 0.
tests/unit/Executor/StorageFactoryTest.php	Restores tests for the reverted behavior while removing coverage that ensured bucket 0 remained addressable.
composer.json	Relaxes the storage dependency constraint from ^4.0.2 to ^4.0.
composer.lock	Relocks storage to 4.0.0 and downgrades related transitive packages without an established compatibility defect.
README.md	Restores documentation for placeholder-host and URL-based S3-compatible DSNs.

Prompt To Fix All With AI

### Issue 1
src/Executor/StorageFactory.php:58-60
**Bucket zero loses its namespace**

When an S3 DSN names bucket `0`, this condition treats it as empty and omits it from `$bucketRoot`, causing reads and writes to target the root namespace instead of bucket `0`.

```suggestion
                $bucketRoot = $bucket === ''
                    ? $root
                    : \rtrim($bucket . '/' . \ltrim($root, '/'), '/');
```

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

_{Reviews (1): Last reviewed commit: "Revert "fix(storage): address the DSN bu..." | Re-trigger Greptile}

[greptile-apps]

Bucket zero loses its namespace

When an S3 DSN names bucket 0, this condition treats it as empty and omits it from $bucketRoot, causing reads and writes to target the root namespace instead of bucket 0.

Suggested change

	$bucketRoot = ($bucket === '' || $bucket === '0')
	? $root
	: \rtrim($bucket . '/' . \ltrim($root, '/'), '/');
	$bucketRoot = $bucket === ''
	? $root
	: \rtrim($bucket . '/' . \ltrim($root, '/'), '/');

Prompt To Fix With AI

This is a comment left during a code review.
Path: src/Executor/StorageFactory.php
Line: 58-60

Comment:
**Bucket zero loses its namespace**

When an S3 DSN names bucket `0`, this condition treats it as empty and omits it from `$bucketRoot`, causing reads and writes to target the root namespace instead of bucket `0`.

```suggestion
                $bucketRoot = $bucket === ''
                    ? $root
                    : \rtrim($bucket . '/' . \ltrim($root, '/'), '/');
```

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.