chore: land PRs #7-#10 on main

[Meldiron]

PRs #7, #8, #9 and #10 were each merged into fix-required-attributes rather than into main, so their changes never reached the default branch. This lands them.

Included:

• fix: allow any data type and omit absent optional attributes #7 fix: allow any data type and omit absent optional attributes
• feat: add dataschema context attribute #8 feat: add dataschema context attribute
• feat: add extension attribute support #9 feat: add extension attribute support
• feat: add JSON event format support #10 feat: add JSON event format support

Plus one fix: #9 removed withExtension()/getExtension() while #10's tests still called them, so the combination left the suite failing. Those two tests now use the readonly extensions property.

composer test, composer lint and composer check all pass.

🤖 Generated with Claude Code

[greptile-apps]

Greptile Summary

This PR expands the CloudEvent model and serialization support.

• Allows arbitrary event data and omits absent optional attributes.
• Adds dataschema and extension attributes.
• Adds CloudEvents JSON-format parsing, serialization, and binary payload handling.
• Extends README documentation and unit coverage.

Confidence Score: 4/5

The PR should not merge until JSON serialization rejects invalid constructor extensions and preserves binary payloads that happen to contain valid UTF-8.

Constructor-supplied extensions can produce JSON rejected by the library’s own parser, and data_base64 payloads are reclassified as ordinary data whenever their decoded bytes are valid UTF-8.

Files Needing Attention: src/CloudEvents/CloudEvent.php; tests/CloudEvents/CloudEventTest.php

Important Files Changed

Filename	Overview
src/CloudEvents/CloudEvent.php	Adds optional attributes, extensions, and JSON-format support, but permits invalid constructor extensions to be serialized and loses binary representation for Base64 payloads containing valid UTF-8.
tests/CloudEvents/CloudEventTest.php	Adds broad coverage for the new model and JSON behavior, but binary round-trip coverage omits Base64 payloads whose decoded bytes are valid UTF-8.
README.md	Documents dataschema and omission of absent optional attributes without introducing an independently actionable issue.

Prompt To Fix All With AI

### Issue 1
src/CloudEvents/CloudEvent.php:143
**Invalid extensions reach serialized output**

When a caller constructs an event with an invalid extension such as `data_base64` and serializes it without calling `validate()`, `toArray()` merges that extension directly into the output. With ordinary `data`, this emits both `data` and `data_base64`, producing JSON that the library's own `fromJson()` rejects.

### Issue 2
src/CloudEvents/CloudEvent.php:190
**Binary representation is discarded**

When `data_base64` decodes to valid UTF-8 bytes, `fromJson()` stores only the decoded string and `toJson()` subsequently emits it as ordinary `data`. For example, `"data_base64":"aGVsbG8="` becomes `"data":"hello"`, causing downstream consumers to interpret an opaque binary payload as text or JSON.

---

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

_{Reviews (1): Last reviewed commit: "fix: update JSON tests for the removed e..." | Re-trigger Greptile}

[greptile-apps]

Invalid extensions reach serialized output

When a caller constructs an event with an invalid extension such as data_base64 and serializes it without calling validate(), toArray() merges that extension directly into the output. With ordinary data, this emits both data and data_base64, producing JSON that the library's own fromJson() rejects.

Prompt To Fix With AI

This is a comment left during a code review.
Path: src/CloudEvents/CloudEvent.php
Line: 143

Comment:
**Invalid extensions reach serialized output**

When a caller constructs an event with an invalid extension such as `data_base64` and serializes it without calling `validate()`, `toArray()` merges that extension directly into the output. With ordinary `data`, this emits both `data` and `data_base64`, producing JSON that the library's own `fromJson()` rejects.

---

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

[greptile-apps]

Binary representation is discarded

When data_base64 decodes to valid UTF-8 bytes, fromJson() stores only the decoded string and toJson() subsequently emits it as ordinary data. For example, "data_base64":"aGVsbG8=" becomes "data":"hello", causing downstream consumers to interpret an opaque binary payload as text or JSON.

Prompt To Fix With AI

This is a comment left during a code review.
Path: src/CloudEvents/CloudEvent.php
Line: 190

Comment:
**Binary representation is discarded**

When `data_base64` decodes to valid UTF-8 bytes, `fromJson()` stores only the decoded string and `toJson()` subsequently emits it as ordinary `data`. For example, `"data_base64":"aGVsbG8="` becomes `"data":"hello"`, causing downstream consumers to interpret an opaque binary payload as text or JSON.

---

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