fix: engines ^22.18.0 || >=24.0.0 — exclude EOL Node 23

docs/rfc/implemented/process/2026-07-06-node-22-18-floor.md

@@ -8,10 +8,12 @@ The root `engines.node` was `>=24`, which excluded the entire Node 22 LTS line f
 
 ## Decision
 
-Set `engines.node` to `>=22.18` and treat 22.18 as the tested floor everywhere (CI matrix `['22.18', 24, 26]`, the real-API e2e job on `['22.18', 24]` — floor plus primary line, since the keyless matrix exercises only the mock adapter and the live `fetch`/SSE path runs only in e2e). 22.18 is the *later* of the two feature boundaries the code depends on, so it is the earliest Node version where everything the repo ships and tests runs unflagged:
+Set `engines.node` to `^22.18.0 || >=24.0.0` (Node 22.18+ on the LTS line, or 24+) and test it on the CI matrix `['22.18', 24, 26]` — the real-API e2e job on `['22.18', 24]` (floor plus primary line, since the keyless matrix exercises only the mock adapter and the live `fetch`/SSE path runs only in e2e). Two Node features gate the range, each with its own LTS-line and Current-line unflag point:
 
-- **`node:sqlite` — Node 22.13.** `packages/session-persistence/session-persistence-sqlite` does a top-level `import { DatabaseSync } from 'node:sqlite'`. The module dropped its `--experimental-sqlite` flag requirement in Node 22.13 (backport of the 23.4 change), so any floor ≥ 22.13 loads it without a flag.
-- **Native TypeScript type-stripping — Node 22.18.** The `packages/ui/stdio-agent/tests/built-bin.e2e.ts` smoke boots the published `lib/bin.js` under plain `node` and loads the example's `.ts` plugins (`mock-llm.ts`, `echo-tool.ts`) with no tsx. Native type-stripping — which makes that work — was unflagged in the 22.x LTS line only in 22.18 (before that it needed `--experimental-strip-types`). This is the binding constraint, so it sets the floor.
+- **`node:sqlite`** — `packages/session-persistence/session-persistence-sqlite` does a top-level `import { DatabaseSync } from 'node:sqlite'`. The module dropped its `--experimental-sqlite` flag requirement at **22.13** (LTS) and **23.4** (Current); before those, importing it throws at load.
+- **Native TypeScript type-stripping** — the `packages/ui/stdio-agent/tests/built-bin.e2e.ts` smoke boots the published `lib/bin.js` under plain `node` (no tsx) and loads the example's `.ts` plugins (`mock-llm.ts`, `echo-tool.ts`). Type-stripping is the default from **22.18** (LTS) and **23.6** (Current); before those it needs `--experimental-strip-types`.
+
+On the 22.x line both features clear at **22.18** (the later of 22.13/22.18), so `^22.18.0` is the LTS floor. The range is **disjoint** rather than an open `>=22.18` because the Node **23.0–23.5** window still has at least one feature flagged (sqlite until 23.4, stripping until 23.6): `>=22.18` would advertise support there, where the sqlite backend throws `ERR_UNKNOWN_BUILTIN_MODULE` at load. Node 23 is non-LTS and already end-of-life, so rather than carve out `>=23.6` the range skips the whole line and resumes at `>=24.0.0` — the same shape several of the repo's own dependencies already declare (`^22.18.0 || >=24.11.0`).
 
 `@types/node` is pinned to the 22.x line (`^22.20.0`) to match the floor: reaching for a Node 23+/24+/25+ API then fails `tsc` on every machine and in the typecheck gate, rather than compiling clean and surviving to a runtime failure only the 22.18 matrix leg could catch. The whole tree typechecks clean against the Node 22 type surface today, so the pin costs nothing.
 
@@ -26,5 +28,7 @@ Set `engines.node` to `>=22.18` and treat 22.18 as the tested floor everywhere (
 
 - **Floor `>=22.13` (the `node:sqlite` boundary) plus `--experimental-strip-types` in the built-bin smoke on 22.13–22.17.** Rejected: it adds a version-conditional test flag for one narrow range and dresses up an experimental-flag dependency as first-class support. 22.18 clears both boundaries with zero test special-casing, and the five-patch gap below it buys nothing real.
 - **Keep `>=24`.** Rejected: it excludes Node 22 LTS with no runtime justification once the two boundaries above are known.
+- **Open-ended `>=22.18`.** Rejected: it advertises support for Node 23.0–23.5, where `node:sqlite` (until 23.4) or type-stripping (until 23.6) is still flagged, so the sqlite backend throws at load. The disjoint `^22.18.0 || >=24.0.0` matches the real runtime boundary.
+- **Include Node 23.6+ (`^22.18.0 || >=23.6.0`).** Rejected: 23.6+ does run both features unflagged, but Node 23 is end-of-life — advertising a dead release line adds a range term (and, to back it, a CI leg) for a runtime no deployment should use. 24 is the meaningful resumption point, and the 22.18 and 24 legs already bracket the same unflagged code paths.
 - **Matrix `[22, 24, 26]` (latest 22.x) instead of pinning `22.18`.** Rejected: "latest 22.x" drifts upward over time and would silently stop exercising the declared floor. Pinning the floor version is what makes the matrix a proof of the claim rather than a proof of some newer 22.x.
 - **Keep `@types/node` ahead of the floor (`^25`).** Rejected: types ahead of the runtime floor let a Node 24/25-only API compile clean and fail only at runtime on 22.18 — exactly the "green types, broken product" gap. Pinning `@types/node` to the 22.x line turns that into a compile error everywhere, and the tree already typechecks clean against the Node 22 surface, so the pin is free.