P1: integrate context-owned HTTP resilience into Java main

[philipgreat]

Scope

Isolated the Java HTTP foundation from the broader P1 development branch onto current main: Context-owned facade, bounded connect/request/whole-call timeouts, explicit retry and POST ambiguity, circuit/rate limits, cancellation, trace carrier and safe telemetry. This PR excludes committed mutation replication and Secret Provider.

Verification

• HTTP focused Maven test passed.
• HTTP runtime-owned example passed twice.
• Core, runtime, HTTP, and OpenTelemetry module test reactor passed.
• git diff --check passed.

Boundaries

This is source/main integration only. Production routing/privacy qualification, immutable package consumers, public release, and generator adoption retain independent gates. Controlled Linux SYN-drop and OpenObserve probes have earlier fixed-source evidence; this PR does not claim those environment-dependent gates were rerun here.