Preserve index prefix lengths and order in SHOW CREATE TABLE primary keys - #500

## Release `3.0.2`

Version bump and changelog update for release `3.0.2`.

**Changelog draft:**
* Fix schema reconstruction with native numeric results
([#506](#506))
* Fix lexer edge cases and string handling
([#505](#505))
* Preserve index prefix lengths and order in SHOW CREATE TABLE primary
keys
([#500](#500))
* Align savepoint handling with MySQL semantics
([#496](#496))

**Full changelog:**
v3.0.1...release/v3.0.2

## Next steps

1. **Review** the changes in this pull request.
2. **Push** any additional edits to this branch (`release/v3.0.2`).
3. **Merge** this pull request to complete the release.

Merging will automatically build the plugin ZIP, create a [GitHub
release](https://github.com/WordPress/sqlite-database-integration/releases),
and deploy to
[WordPress.org](https://wordpress.org/plugins/sqlite-database-integration/).

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **Bug Fixes**
  - Improved schema reconstruction when handling native numeric results.
  - Corrected lexer edge cases and string processing.
- Fixed index prefix lengths and ordering in `SHOW CREATE TABLE` output
for primary keys.
  - Improved savepoint handling to better match MySQL behavior.

- **Release**
  - Updated the SQLite integration to version 3.0.2.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Brings in WordPress#496 (MySQL savepoint semantics), WordPress#500 (index prefix lengths in
SHOW CREATE TABLE) and WordPress#505 (lexer edge cases and string handling).

The one conflict is in the engine's transaction and savepoint handling: WordPress#496
reintroduced direct connection->query('BEGIN IMMEDIATE'/'COMMIT'/'ROLLBACK')
plus its own $in_transaction and $savepoint_names tracking, while this branch
routes transaction control through WP_SQLite_Connection_Interface so that remote
backends can implement it themselves.

Resolved by keeping upstream's semantics and this branch's dispatch: the new
savepoint-name bookkeeping (MySQL replaces a savepoint on name reuse where
SQLite shadows it, RELEASE and ROLLBACK TO drop the savepoints created after the
named one, and an unknown name raises the new exception) is preserved, but the
statements go through begin_transaction()/commit()/rollback()/savepoint()/
release_savepoint()/rollback_to_savepoint(). Upstream's engine-level
$in_transaction polyfill is dropped as dead state, because inTransaction() on
this branch already delegates to the connection.

Verified: packages/mysql-on-sqlite 1080 tests, 1429272 assertions, no failures.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>