[O2B-1474] Add kafka producer for beam mode change on stable beams

[graduta]

PR which:

• adds Kafka Producer interface for reuse
• adds beam mode change kafka producer to send events when "out of" & "into" stable beams
• adds proto files that are to be used for publishing kafka events
• adds protoc generated javac classes

[Copilot]

Pull Request Overview

Adds a Kafka producer to emit beam mode change events (for stable beams lifecycle) serialized with Protocol Buffers, integrates it into the DIP message processing flow, and introduces the corresponding .proto schemas and documentation updates.

• Introduces common and event protobuf schemas (BeamInfo, BeamMode, Ev_BeamModeEvent).
• Adds a generic Kafka producer wrapper and a BeamMode-specific producer, wiring it into DipMessagesProcessor and lifecycle management in AliDip2BK.
• Updates README with purpose, requirements, and the new published event topic.

Reviewed Changes

Copilot reviewed 7 out of 9 changed files in this pull request and generated 11 comments.

Show a summary per file

File	Description
src/alice/dip/protos/protos/common.proto	Adds common protobuf types (User, WorkflowTemplateInfo, BeamInfo, BeamMode) used by events.
src/alice/dip/protos/events.proto	Defines event messages including Ev_BeamModeEvent and references common types.
src/alice/dip/kafka/KafkaProducerInterface.java	Provides a generic Kafka producer wrapper used by the BeamMode producer.
src/alice/dip/kafka/BeamModeEventsKafkaProducer.java	Implements producer for beam mode events; serializes to protobuf and sends to Kafka.
src/alice/dip/DipMessagesProcessor.java	Integrates the BeamMode producer and emits events on beam mode transitions.
src/alice/dip/AliDip2BK.java	Creates, injects, and closes the BeamMode Kafka producer in the app lifecycle.
README.md	Updates project description, requirements, and documents the new Kafka topic.

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[Copilot]

Pull Request Overview

Copilot reviewed 8 out of 10 changed files in this pull request and generated 3 comments.

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[Copilot]

Pull Request Overview

Copilot reviewed 9 out of 11 changed files in this pull request and generated 4 comments.

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[graduta]

Closed in favour of: #15