tooling: per-suite conformance filter + live-check.sh; note render-diff to vm-extensions

- conformance.sh [suite] runs ONE suite (filters the SUITES array so result-parser
  indices stay aligned; all MODULES still load). 'conformance.sh sxtp' = 0.3s vs ~8min.
- lib/host/live-check.sh: non-browser live smoke — boot ephemeral host, login, seed a
  post (exercises form-ingest write), print status|content-type|body-head per path,
  assert reads are text/sx + no JSON leak + no 5xx. The counterpart to run-picker-check.sh.
- plans/NOTE-render-diff-for-vm-ext.md: defer host_render_diff (JIT-vs-interpreter
  regression oracle) to the sx-vm-extensions loop — it's their fix's oracle, not a host
  feature; building it from loops/host would fork JIT-engine understanding.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

plans/host-dev-tooling.md

@@ -16,7 +16,11 @@ eyeballed live** (login + curl + grep the rendered HTML). The tools below make t
 eventually, automatic. See `[[feedback_host_serving_jit_iteration]]`,
 `[[project_sx_engine_harness_tests]]`.
 
-## 1. `host_conformance(suite?)` — per-suite, fast (trivial; do first)
+## 1. `host_conformance(suite?)` — per-suite, fast (trivial; do first) — DONE 2026-06-30
+
+`conformance.sh [suite] [-v]` now takes an optional suite name (filters the SUITES array so
+result-parser indices stay aligned; all MODULES still load). `conformance.sh sxtp` runs in
+**0.3s** vs ~8min for the full Datalog-heavy run. Bad name → error listing valid suites.
 
 Today `conformance.sh` runs all 11 suites (~10 min, all-or-nothing). Iterating on one subsystem
 means hand-extracting the `MODULES` array to build a focused runner (done by hand this session).
@@ -28,7 +32,13 @@ means hand-extracting the `MODULES` array to build a focused runner (done by han
 - **Effort:** ~1 line of bash + arg parse. **Payoff:** every remaining iteration of this loop.
 - **Not MCP-shaped on its own** — the bash arg is 90% of the value; wrap only if convenient.
 
-## 2. `host_live_check(seed, requests)` — rendered HTML from an ephemeral server (high ROI)
+## 2. `host_live_check` — rendered HTML from an ephemeral server (high ROI) — DONE 2026-06-30
+
+Built as `lib/host/live-check.sh` (shell, the right grain — matches run-picker-check.sh). Boots
+an ephemeral host, logs in, seeds a post (exercising the form-ingest write path), then prints
+`status | content-type | body-head` for `/health /posts /feed / /<seeded>/` (or paths passed as
+args). Asserts reads are `text/sx`, no JSON leak, no 5xx, non-empty bodies — ~10s, no browser.
+Caught nothing new today (the wire was already verified) but it's the standing pre-deploy smoke.
 
 Generalize `lib/host/playwright/run-picker-check.sh` from "the picker" to "any route." Boot an
 ephemeral host server on a temp persist dir, seed posts, run an **authed request sequence**, and