[eldmark]

What

Brings this branch up to par with branch 5.9:

1. Listing optimization — ports optimization: move filter and order logic to the query and fix: order by foreign relation.
2. Column filters — ports feat: search by column, multifilter.
3. Tests — adds a PHPUnit suite covering the methods that build the listing query.
4. README — documents the PHP and Laravel versions this branch supports.

Why

data() fetched every row of the table and then filtered, sorted and sliced it
in memory with Collection methods, so the cost of a page grew with the size of
the table. It also ran one extra query per row for multi fields.

How

Search, ordering and pagination now run in the database:

• Each filter row sent by the view as filters[] becomes a WHERE: a plain
  column with LIKE, a relation column or a multi field through whereHas,
  and a raw expression through whereRaw.
• Ordering by a relation column uses a correlated subquery
  (getRelationExistenceQuery + orderByRaw) instead of sortBy in memory.
• Only the requested page is read, with offset/limit.
• multi fields are eager loaded once per page, removing the N+1.
• Aliased expressions (col AS alias) are stripped before being used inside
  WHERE/ORDER BY, so filtering or ordering by an aliased column no longer
  produces invalid SQL.
• The DataTables global search box is replaced by the filter rows, matching the
  behaviour of branch 5.9.

Compatibility

The public API is unchanged: setField/setCampo, setWhere, setOrderBy
and the JSON response shape are the same, and the runtime composer.json
constraints were not touched. The helpers avoid APIs newer than what this
branch already requires (no short list destructuring, no Builder passed to
orderBy), so the branch keeps working on the same Laravel versions as before.

Testing

composer install && vendor/bin/phpunit — 21 tests, 45 assertions, green.

The suite asserts on the SQL and the bindings each method produces: local and
relation filters, multi filters, raw expressions, malformed or empty filters,
alias stripping, correlated-subquery ordering, raw-expression ordering, unknown
relation fallback, and the field/select helpers. It needs Eloquent but never a
database server, so no query is executed and it runs anywhere composer runs.
PHPUnit, illuminate/database and illuminate/routing are require-dev only,
so nothing changes for consumers of the package.

A manual pass over one listing per project is still recommended before tagging
a release, since the suite does not assert against live rows.

Docs

README.md now states the PHP and Laravel versions supported by this branch,
plus a matrix for every branch of the repo. The Laravel bounds are derived from
the framework APIs each branch calls, because the composer.json constraints
were never updated (several branches still declare php >= 5.3.0).