Camel 23523 kafka batch interval reset

[FNaughton]

Description

Summary

• Fixes a bug where intervalWatch is never reset when exchangeList transitions
  from empty to non-empty, unlike timeoutWatch which is reset at that point.
• After an idle period longer than batchingIntervalMs, the watch is pre-expired,
  causing hasExpiredRecords() to fire on the very next poll that returns records,
  flushing a prematurely small batch.
• Fix: add intervalWatch.restart() alongside timeoutWatch.takenAndRestart() in
  the exchangeList.isEmpty() branch of processExchange().

Test plan

• New IT KafkaBatchingIntervalResetAfterIdleIT fails on unfixed code and
  passes after the fix
• All five pre-existing batching ITs pass unchanged

Target

• I checked that the commit is targeting the correct branch (Camel 4 uses the main branch)

Tracking

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Apache Camel coding standards and style

• I checked that each commit in the pull request has a meaningful subject line and body.

• I have run mvn clean install -DskipTests locally from root folder and I have committed all auto-generated changes.

[github-actions]

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[github-actions]

🧪 CI tested the following changed modules:

• components/camel-kafka

⚠️ Some tests are disabled on GitHub Actions (@DisabledIfSystemProperty(named = "ci.env.name")) and require manual verification:

• components/camel-kafka: 2 test(s) disabled on GitHub Actions

All tested modules (8 modules)

• Camel :: JBang :: MCP
• Camel :: JBang :: Plugin :: Route Parser
• Camel :: JBang :: Plugin :: TUI
• Camel :: JBang :: Plugin :: Validate
• Camel :: Kafka
• Camel :: Launcher :: Container
• Camel :: YAML DSL :: Validator
• Camel :: YAML DSL :: Validator Maven Plugin

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