Keep the message that hits the limit in the queue

[KalimeroMK]

Q	A
Is bugfix?	✔️
New feature?	❌
Breaks BC?	❌
Tests added?	✔️

What does this PR do?

queue:run --limit=1 over two queued messages prints Messages processed: 1. and leaves the queue empty. The second message is discarded without ever reaching a handler.

$producer->push(new GenericMessage('simple', null));
$producer->push(new GenericMessage('simple', null));

$consumer->run(1);                  // 1
$adapter->getMessagesList();        // [] — expected 1 message still queued

Cause

QueueConsumer::run() returns false from the callback for the message that trips the limit, without handling it. InMemoryAdapter::runExisting() unsets the message anyway, before it looks at what the callback returned:

$result = $handlerCallback($this->messages[$this->current]);
unset($this->messages[$this->current]);   // stubs/InMemoryAdapter.php:54
$this->current++;

Both shipped adapters already read false as "not consumed":

• queue-redis — if ($result) { $this->provider->delete(...); } (Adapter.php:35)
• queue-amqp — if ($this->messageConsumed = $callback($message)) { basic_ack(); } else { basic_nack($tag, false, true); } (ExistingMessagesConsumer.php:42)

So the stub is the outlier, and AdapterInterface never said which reading was intended — it only said "Returns false if it cannot continue handling messages".

Fix

InMemoryAdapter keeps a message the callback refused, and runExisting()/subscribe() state the contract the other adapters already implement. QueueConsumer is unchanged.

Not addressed here

One bit cannot carry both "was this message consumed?" and "should I continue?". When the loop stops after a message was handled (SignalLoop on SIGTERM), the callback returns false for a message that was processed, so it is kept and processed again on the next run. Every adapter behaves this way today; splitting the two signals is an AdapterInterface change and belongs in its own issue: #346.

Validation

Both new assertions fail without the fix (actual size 0 matches expected size 1, actual size 1 matches expected size 2) and pass with it. Full suite: 280 tests, 516 assertions, OK. Psalm and PHP CS Fixer clean.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.58%. Comparing base (7c79c3b) to head (a258088).

Additional details and impacted files

@@            Coverage Diff            @@
##             master     #340   +/-   ##
=========================================
  Coverage     94.58%   94.58%           
  Complexity      373      373           
=========================================
  Files            59       59           
  Lines           978      978           
=========================================
  Hits            925      925           
  Misses           53       53           

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[KalimeroMK]

Pushed a follow-up: the fix left return false inside the callback reachable only when the loop asks to stop, which no test covered (codecov caught it, -1 line). Adding that test showed run() returned one less than it handled in that case — the message is always handled by the time the callback decides whether to continue — so the count moved out of the early return.