fix(render): honor proxy environment variables in Chrome launches

[miguel-heygen]

Chrome render launches now translate HTTP_PROXY, HTTPS_PROXY, and ALL_PROXY into native proxy settings through one shared resolver. Lowercase variables take precedence, NO_PROXY covers hosts and their subdomains, and localhost, IPv4 loopback, and IPv6 loopback always remain direct so local preview and composition servers stay reachable. URLs containing proxy credentials fail with a clear error before Chrome starts.

The CLI launch owner, engine capture pool, GPU probes, and audio browser launches share this policy. Resolved flags are part of the pool fingerprint, so changing the proxy cannot reuse a browser with an older policy. There is no new CLI flag, configuration field, or composition format.

Validation: mapping and refusal tests, a regression that fails on main when a changed proxy reuses the old browser, and real Chrome tests through both launch owners. A local stub receives an external HTTP fetch and denies its HTTPS CONNECT, while the local composition page bypasses the proxy. Deliberate mutations verify the mapping tests detect broken precedence, scheme selection, credentials refusal, bypass rules, and unset-variable behavior. Targeted typechecks and pre-commit checks pass.

[github-actions]

Edit accuracy: accurate 2059 (base branch 2059), smooth 1583 of those

The gate passes.
Smoothness is reported in the artifact, not gated. A case fails only if it fails 2 of 3 runs.

Quarantined, measured but not gated (0)

Unstable (3)

• crop-none-px-r0-root-z200: tracking 0.02, pressJump 0, drop 40.03, reload 40, render 39.98, renderKey -, undo true, teleport true / tracking 0.02, pressJump 0, drop 0.04, reload 0.04, render 0.03, renderKey -, undo true, teleport true / tracking 0.02, pressJump 0, drop 0.04, reload 0.04, render 0.03, renderKey -, undo true, teleport true
• crop-none-px-r30-root-z50: tracking 0.05, pressJump 0, drop 40.14, reload 40.14, render 34.74, renderKey -, undo true, teleport true / tracking 0.05, pressJump 0, drop 0.14, reload 0.14, render 0.26, renderKey -, undo true, teleport true / tracking 0.05, pressJump 0, drop 0.14, reload 0.14, render 0.26, renderKey -, undo true, teleport true
• crop-none-px-r30-root-z100: tracking 0.04, pressJump 0, drop 40.08, reload 40.08, render 34.74, renderKey -, undo true, teleport true / tracking 0.04, pressJump 0, drop 0.08, reload 0.08, render 0.26, renderKey -, undo true, teleport true / tracking 0.04, pressJump 0, drop 0.08, reload 0.08, render 0.26, renderKey -, undo true, teleport true