CAMEL-23345: Document HTTP 429 Retry-After hang and automaticRetriesDisabled workaround

[davsclaus]

Summary

• Adds a new "Handling HTTP 429 Too Many Requests" section to the HTTP component docs explaining that Apache HttpClient 5 (since 5.5.x) honors the Retry-After header on 429 responses, which can cause the component to appear hung for long durations (e.g. Retry-After: 3600 → 1-hour wait).
• Documents automaticRetriesDisabled=true as the workaround, with both Java and URI option examples.
• Improves the @Metadata description of automaticRetriesDisabled on HttpComponent to mention the 429 use case.

Test plan

• Documentation-only change; no functional code changed.
• Full root build (mvn install -Dquickly) completed successfully with regenerated catalog JSON files included.

Fixes: https://issues.apache.org/jira/browse/CAMEL-23345
Upstream: https://issues.apache.org/jira/browse/HTTPCLIENT-2421

Claude Code on behalf of Claus Ibsen

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🧪 CI tested the following changed modules:

• catalog/camel-catalog
• components/camel-http
• dsl/camel-componentdsl

ℹ️ Dependent modules were not tested because the total number of affected modules exceeded the threshold (50). Use the test-dependents label to force testing all dependents.

Build reactor — dependencies compiled but only changed modules were tested (3 modules)

• Camel :: Catalog :: Camel Catalog
• Camel :: Component DSL
• Camel :: HTTP

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