fix: preserve Streamlit analysis across stops

[ninedter]

What changed

• Move Streamlit-triggered PCAP analysis into the existing process-backed job queue.
• Persist job progress and bounded UI restoration artifacts in the case database.
• Reattach recent background runs after a Streamlit session reset or page reload.
• Support background LLM report generation and report-only regeneration without rerunning packet analysis.
• Update English and Traditional Chinese user documentation and add regression coverage.

Why

Streamlit previously ran the full analysis inside the page's script thread and copied results into session state only after completion. Pressing the upper-right Stop control terminated that thread, so in-progress work disappeared and had to be restarted.

User impact

Pressing Stop now pauses the display while the worker continues. Progress remains durable in SQLite, and completed evidence is autosaved and restored when the page reconnects. Completed work survives page reloads; a full server or container restart can still interrupt an in-flight process-pool job.

Validation

• make verify
• 1,015 passed, 22 skipped
• Docker build and verification completed successfully before publication
• Streamlit render smoke completed without exceptions