Draft. First of an incremental series decomposing the ironclaw_reborn_composition god-crate (~132k lines), one isolated crate per PR so each lands fast before main diverges. This PR extracts the foundational, product-agnostic HTTP middleware kit. Supersedes the stale big-bang draft #5135.

Why incremental

ironclaw_reborn_composition has grown to ~132k lines by accreting product/service domains (Slack, product-auth, LLM-admin, extension/MCP) plus a generic HTTP middleware kit behind cfg-gated features. The full decomposition design was ratified by a two-model design council — see docs/plans/2026-06-21-composition-crate-decomposition.md. An earlier branch did all six extractions at once but went stale against 168 commits of parallel development on the same crate. This series lands them one crate at a time.

This PR: extract ironclaw_reborn_http_kit

Two tightly-coupled, behavior-preserving steps:

1. Invert the route-mount seam. webui_serve no longer hardcodes product route families. The serving core is now product-agnostic compose_webui_v2_app(api, config); products supply generic ProtectedRouteMount / PublicRouteMount fragments via WebuiServeConfig::with_{protected,public}_route_mount. ProtectedRouteMount::operator_gated(...) reproduces the Slack channel-routes admin gating generically. The product-aware lowering (turning bundle.product_auth into mounts) moved to webui.rs, which wraps the core. The Slack route factories now return the generic mount types.

2. Extract the crate. The six descriptor-driven middleware modules move out of composition into the new crate:

ironclaw_reborn_composition/src/webui_serve.rs        → http_kit/src/serve.rs
                            webui_body_limit.rs        →         body_limit.rs
                            webui_rate_limit.rs        →         rate_limit.rs
                            webui_route_match.rs       →         route_match.rs
                            webui_ws_origin.rs         →         ws_origin.rs
                            webui_operator_auth.rs     →         operator_auth.rs

ironclaw_reborn_http_kit depends only on substrate (ironclaw_auth, ironclaw_host_api, ironclaw_product_workflow, ironclaw_webui_v2(+static)) — zero product knowledge. Composition re-exports the same public symbols via pub use ironclaw_reborn_http_kit::…, so reborn_cli, reborn_webui_ingress, and all downstream paths compile unchanged.

Verification (green)

Note on parallel flakiness: the full composition suite shows a few non-deterministic failures in runtime::tests under parallel load (a different set each run). These are pre-existing on main — several local_dev_runtime_* / nearai tests share process-global state (env vars for the nearai session token, OS keychain, temp files) and race under high parallelism. They pass deterministically when run serially (134/134 above) and in isolation, and this PR only touches the webui HTTP middleware — orthogonal to nearai/runtime bootstrapping. Flagging as a pre-existing test-isolation issue, not introduced here.

Next in the series

product_auth → slack_host → llm_admin → extension_host, plus relocating the OutboundDeliveryTargetProvider vocabulary into ironclaw_product_workflow (the Slack-cycle prerequisite). Each a separate, individually-verified PR.

🤖 Generated with Claude Code