refactor(docker): consolidate JVM options and improve dynamic memory computation

[balazs-szucs]

Closes: #5866

Description of Changes

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[Copilot]

Pull request overview

Refactors the container startup/JVM configuration to consolidate JVM option selection into a single _JVM_OPTS source and adjusts dynamic JVM memory percentage computation in init-without-ocr.sh.

Changes:

• Simplified dynamic memory computation (removed profile-based branches; adjusted Initial/Max RAM % for mid/large containers).
• Consolidated JVM option selection to JAVA_BASE_OPTS > _JVM_OPTS > fallback defaults, and added dynamic ConcGCThreads sizing based on CPU count.
• Updated embedded Docker images to set a single _JVM_OPTS (Shenandoah generational) instead of balanced/performance profiles.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 5 comments.

File	Description
scripts/init-without-ocr.sh	Removes profile-based selection, tweaks memory sizing, adds CPU-based ConcGCThreads, consolidates JVM option sourcing.
docker/embedded/Dockerfile.ultra-lite	Replaces profile env vars with single _JVM_OPTS default.
docker/embedded/Dockerfile.fat	Replaces profile env vars with single _JVM_OPTS default (currently has a malformed flag string).
docker/embedded/Dockerfile	Replaces profile env vars with single _JVM_OPTS default.

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