Fix REST path encoding, Java Unicode escaping, and monitor initialization

[hoco-scy]

Summary

This PR fixes four independent failures observed while generating and running EvoMaster tests across the WebFuzzing SUT suite:

• Resolved REST path fragments can fail or be corrupted for lone surrogates, supplementary Unicode characters, and non-ASCII characters.
• Java Mongo initialization source can contain literal backslash-u sequences that interact with Java Unicode preprocessing.
• Java request-body source can collapse literal backslash-u sequences into invalid or value-changing Unicode escapes.
• Disabled process monitoring still initializes and deletes shared monitor output state, creating a concurrent filesystem race.

Changes

• Encode non-ASCII resolved REST path fragments by Unicode code point and use URI raw paths, preserving valid surrogate pairs and handling isolated surrogates safely.
• Escape Java-only Mongo EJSON literal backslash-u runs with octal backslash escapes while preserving genuine Unicode escapes and runtime values.
• Preserve doubled source backslashes for Java BODY output so literal backslash-u values survive Java Unicode preprocessing.
• Initialize process-monitor output only when process monitoring is enabled.

Scope

• REST encoding applies to resolved/static path fragments, including fragments around OpenAPI link variables. Runtime link-variable values remain outside this change.
• Mongo octal escaping applies only to Java output. Kotlin keeps its existing escaping behavior.
• BODY escaping changes only Java JUnit 4/5 output. Kotlin, JavaScript, and Python behavior is unchanged.
• Process-monitor behavior changes only when the monitor is disabled.

Tests

• Added and extended regression coverage for BMP, supplementary, and isolated-surrogate REST path values; static fragments around runtime REST link variables; literal and genuine Unicode sequences in Java Mongo EJSON; Java BODY escaping through the JSON writer; and disabled process-monitor output isolation.
• Local targeted suite: 64 tests passed with no failures, errors, or skips.
• Additional local core coverage passed for all modified areas. Cases requiring unavailable external LLM/HTTP services or uncached Docker images are left to the fork CI environment.
• Experimental validation confirmed the affected SUT generation and execution paths.

[arcuri82]

hi @hoco-scy !
you are a student of @man-zhang isn't it?
thanks for this PR ;)
as Man told you about docs/for_msc_bsc_students.md? once CI passes, ask @man-zhang for a review, and, when she will accept your updates/changes, she will ask for my review here on GitHub.
also, no need to create entries under issues (that is mainly for external users), you can just discuss them here directly in the PR description
thanks ;)

[hoco-scy]

Hi @arcuri82,

Yes, I am a student of @man-zhang.

Thank you for the guidance. I apologize that I had not read docs/for_msc_bsc_students.md before opening this PR, so I followed my usual personal development workflow and created separate issues for the fixes.

I have now read the document and understand the expected internal contribution process. I will close the issues, keep the technical context in the PR description, make sure the CI process is completed on my fork, and then follow the review flow through @man-zhang.

Thank you again for your time and help.

[hoco-scy]

Hi @man-zhang,

I have addressed both review comments in fe79f8e:

• removed the unnecessary suppression annotation;
• investigated the Kotlin behavior and confirmed that it was affected by the same backslash-u issue;
• extended the fix to Kotlin output while preserving Kotlin dollar-sign escaping;
• added Kotlin JUnit 4/5 coverage and an actual compile-and-runtime regression test;
• added concrete examples to the source comment.

The latest full CI run for the same PR head commit has completed successfully: 22 jobs passed, with only the conditional debug job skipped.

CI run:
https://github.com/hoco-scy/EvoMaster/actions/runs/30246503337

Could you please take another look when convenient?

Thank you.