Feat/grpc tls

[thorrester]

Summary

Adds TLS support and connection tuning options to the gRPC transport layer.

TLS

The gRPC client now automatically negotiates TLS based on the URI scheme. Connections to https:// endpoints use native system roots; http:// connections remain plaintext. No config flag required — URI scheme drives the behavior.

Connection options

GrpcConfig gains five new optional fields for fine-grained connection control:

Field	Default	Description
timeout_secs	None (no limit)	Per-request response timeout
connect_timeout_secs	None (no limit)	Initial connection establishment timeout
keep_alive_interval_secs	None (disabled)	HTTP/2 keepalive ping interval
keep_alive_timeout_secs	None (disabled)	Time to wait for keepalive ping response
keep_alive_while_idle	None (disabled)	Send keepalives even with no active streams

All fields are optional and default to the previous behavior (no timeouts, no keepalives).

Internal refactor

• Extracted build_channel as a standalone async function — centralizes endpoint construction and TLS branching, removes duplication between GrpcClient::new and health_check.
• health_check now reuses the existing Channel stored on the client instead of opening a new connection per call.
• Channel is stored on GrpcClient to support channel reuse across all service clients.

Changes

• crates/scouter_settings/src/grpc.rs — added five new fields to GrpcConfig and its constructor
• crates/scouter_tonic/src/client.rs — build_channel function with TLS detection and connection option application; Channel
  stored on GrpcClient; health_check reuses stored channel
• py-scouter/python/scouter/_scouter.pyi / stubs/scouter.pyi — updated stubs with new GrpcConfig fields and docstrings

Usage

from scouter import GrpcConfig

# TLS with keepalives (recommended for cloud deployments)
config = GrpcConfig(
    server_uri="https://scouter.example.com:443",
    username="user",
    password="pass",
    connect_timeout_secs=10,
    timeout_secs=30,
    keep_alive_interval_secs=20,
    keep_alive_timeout_secs=5,
    keep_alive_while_idle=True,
)

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 62.59%. Comparing base (b82477a) to head (ffca52c).
⚠️ Report is 5 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #218   +/-   ##
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  Coverage   62.59%   62.59%           
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  Files          18       18           
  Lines         262      262           
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  Hits          164      164           
  Misses         98       98           

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