Blobber monitoring

we need a performance measurement code in the gosdk

1. for every block upload/download we need to register the time spent for each blobber, some simple message
2. all this messages we need to push to a channel, no-op by default.
3. wasm can collect this messages in background task analyze and decide which blobber is bad

also we will use exactly same mechanics for global monitoring tool (alloc crawler)

1. we will create different allocations on different blobbers, keeping all pairs in pool
2. crawler will continuously take pairs from the pool and make upload/download generating the same messages with gosdk
3. timings can be stored to any local db, later crawler can build statistics and ranks for all the blobbers based on it

https://0chain.slack.com/archives/G01EXH6EYC9/p1734969371661059

Look at the gosdk code for block upload/download operations to understand where timing measurements can be inserted. Identify the channel structure for messages and the default no-op behavior. Review existing monitoring or crawler components to see how messages are collected and analyzed. The goal is to produce timing data per blobber and allocation for later statistical ranking.

Written by the indexing model from the issue text.