[ENH]: add request timing to metering

[c-gamble]

This PR uses the chroma-metering library introduced in #4868 to add execution timing to requests received on the frontend.

⚠️ #4868 should be merged first.

• Tests pass locally with pytest for python, yarn test for js, cargo test for rust

Documentation Changes

N/A

[github-actions]

Reviewer Checklist

Please leverage this checklist to ensure your code review is thorough before approving

Testing, Bugs, Errors, Logs, Documentation

• Can you think of any use case in which the code does not behave as intended? Have they been tested?
• Can you think of any inputs or external events that could break the code? Is user input validated and safe? Have they been tested?
• If appropriate, are there adequate property based tests?
• If appropriate, are there adequate unit tests?
• Should any logging, debugging, tracing information be added or removed?
• Are error messages user-friendly?
• Have all documentation changes needed been made?
• Have all non-obvious changes been commented?

System Compatibility

• Are there any potential impacts on other parts of the system or backward compatibility?
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Quality

• Is this code of a unexpectedly high quality (Readability, Modularity, Intuitiveness)

[propel-code-bot]

Integrate New Metering Library and Add Request Execution Timing to Frontend

This major PR removes the legacy metering event system from the Rust frontend and fully adopts the new chroma-metering library (built in #4868) for all metering and request timing logic. Request execution timing is now attached and centrally tracked on all frontend endpoints (read and write). Metering events are now constructed and submitted according to new context-aware patterns, with improved composability and testability. Large sections of the codebase were updated to implement these changes, and the glue code that bound the old tracing/metering is removed. Secondary changes include introducing new serialization helpers for atomic types, plumbing request time metadata, and making related dependency and project structure updates.

Key Changes:
• Adopted chroma-metering for all request metering and execution timing on Rust frontend endpoints
• Removed old tracing/meterevent code and updated usages to the new context pattern
• Added context containers and request timing logic throughout handlers (e.g., fork/add/update/upsert/delete/query/count endpoints)
• Meter events now attach execution metadata and are submitted after response
• Introduced new MeteringAtomicU64 wrapper for reliable atomic metrics serialization
• Updated dependencies, workspace, and build configuration to support new library

Affected Areas:
• Rust frontend service (service_based_frontend.rs, server.rs)
• All collection and record operation APIs/handlers
• Metering event handling
• Project dependency topology (Cargo.toml, Cargo.lock)
• chroma-metering and helper modules

This summary was automatically generated by @propel-code-bot

[Sicheng-Pan]

given that the event is created in server.rs, should we log the request_completed_at there?

[HammadB]

I think we only need to do latency tracking for

add()/upsert()/update()

get()/query()

Prefer we just do the minimal needed set for the product at hand

[HammadB]

suggest we only do this for events we intend to display this for

[HammadB]

Should we be using duration ?

[Sicheng-Pan]

that can be derived from created_at and completed_at right

Instant works as well

[HammadB]

Would it make more sense to either

• have a start() mutator, that internally sets this, and a finish() mutator that ends it
• directly hydrate a time_elapsed capability ?