Add Spring Boot starters for components missing one

[Croway]

Summary

Adds the Spring Boot starter for every Camel core component that didn't have one yet, checked against apache/camel upstream/main:

• camel-camunda-starter — Camunda 8 Orchestration Clusters
• camel-event-starter — subscribing to Camel internal events
• camel-shell-starter — interactive JLine shell endpoint
• camel-spiffe-starter — SPIFFE Workload Identity
• camel-state-store-starter — pluggable key-value store operations
• camel-ai-resource-starter — route-based read-only AI resources
• camel-pgvector-starter — PostgreSQL pgvector vector database
• camel-langchain4j-ingest-starter — LangChain4j document ingestion
• camel-ibm-watsonx-data-starter — IBM watsonx.data lakehouse

Each is its own commit: generated with starter-create, then built to regenerate the auto-configuration, @ConfigurationProperties, catalog entries, docs page/nav, and dependencies BOM entry, plus a smoke test asserting camel.component.<name>.* properties are correctly bound onto the component bean.

Two smoke tests are worth calling out:

• camel-shell-starter's test resolves the component with autoStart=false, since ShellComponent.doStart() opens a real system terminal and must not run in a headless test.
• The others start the component normally; none of their doStart() implementations make eager network/IO calls (verified by inspection), so property binding can be asserted safely without live external services.

Test plan

• mvn verify passes for each new starter module individually
• mvn verify passes for all 9 new starter modules built together in one reactor run (no cross-module conflicts in the shared catalog/BOM/docs files)