CAMEL-23224: Switch JBang shell to JLine 4 PicocliCommandRegistry

[gnodet]

Summary

• Replace picocli-shell-jline3 with JLine 4's built-in jline-picocli module (PicocliCommandRegistry) which provides proper argument completion via picocli's AutoComplete
• Simplify Shell.java from ~140 lines of manual JLine setup to ~20 lines using JLine 4's Shell.builder() API
• Bump JLine version to 4.0.8

Before

The camel shell REPL only completed command names — no completion for options, option values, or positional parameters.

After

Full argument completion powered by picocli's AutoComplete.complete(): options, option values, positional parameters, completion candidates, and nested subcommands all complete properly.

Note: This PR overlaps with #22161 and #22170 which also migrate to JLine 4's Shell.builder(). The unique contribution here is the picocli argument completion fix (via jline/jline3#1708, included in JLine 4.0.8). Consider cherry-picking the completion fix into #22170 and closing this PR.

Test plan

• camel-jbang-core compiles with JLine 4.0.8 release
• Manual testing of camel shell with tab completion for command arguments

[github-actions]

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[gnodet]

Claude Code on behalf of Guillaume Nodet

Closing — the completion fix (JLine 4.0.8 bump) has been merged into #22170 which is the superset PR.

[github-actions]

🧪 CI tested the following changed modules:

• dsl/camel-jbang/camel-jbang-core
• parent

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 (4 modules)

• Camel :: JBang :: Core
• Camel :: JBang :: Core [jar]
• Camel :: Parent
• Camel :: Parent [pom]