fix(server): Keep each thread's provider event log in its own file#44

What Changed

Each thread's provider event log is now named from a readable prefix of the thread id plus a hash of the full id, so two threads never write to the same file. Events that belong to no thread still go to the shared _global log.

Why

Log file names came from a helper that normalizes thread ids and cuts them to 80 characters. Delegated-task thread ids share long prefixes, so different threads could land in one file and a thread's protocol log mixed in another thread's events. The upstream logger has the same behavior.

Checklist

• This PR is small and focused
• I explained what changed and why
• I included before/after screenshots for any UI changes
• I included a video for animation/interaction changes