Add minimal runtime-side remote session and upstream proxy primitives that model enablement, session identity, token loading, websocket endpoint derivation, and subprocess proxy environment shaping.
This intentionally stops short of implementing the relay or CA download path. The goal is to land real request/env foundations that future remote integration work can build on while preserving the fail-open behavior of the upstream implementation.
Constraint: Must keep the slice minimal and real without pulling in relay networking yet
Constraint: Verification must pass with runtime fmt, clippy, and tests
Rejected: Implement full upstream CONNECT relay now | too large for the current bounded slice
Rejected: Hide proxy state behind untyped env maps only | would make later integration and testing brittle
Confidence: high
Scope-risk: narrow
Reversibility: clean
Directive: Keep remote bootstrap logic fail-open; do not make proxy setup a hard dependency for normal runtime execution
Tested: cargo fmt --all; cargo clippy -p runtime --all-targets -- -D warnings; cargo test -p runtime
Not-tested: live CCR session behavior; relay startup; CA bundle download and trust installation
2de0b0e2af