Drop Deno from the agents and spawn child processes directly (#22)

Co-authored-by: Danny Kim <temeddix@gmail.com>
Co-committed-by: Danny Kim <temeddix@gmail.com>

.agents/memory/bot-agents-child-processes.md

@@ -0,0 +1,39 @@
+---
+description: Child processes use plain node:child_process spawn (explicit stdio, uid/gid, whole env); src/child.ts has exitCode (128+signo) and echo; no execFile maxBuffer
+---
+
+Every call site calls `spawn` from `node:child_process` itself, with
+everything explicit:
+
+- **`uid`/`gid`** of the profile for anything an agent profile runs (each
+  profile is its own UID, 20000+). Never drop them.
+- **`env`** is the whole environment the child gets (a sanitized one for
+  agents); nothing from the coordinator is merged in.
+- **`stdio`**: stdin is `"ignore"` so an agent CLI never waits on input
+  (only `codex login --with-api-key` pipes the token in). Output that is not
+  read is `"ignore"`; output that is read is `"pipe"` and streamed.
+- No `execFile`/`exec`: their `maxBuffer` (1 MiB) kills a chatty child. Read
+  piped streams incrementally instead.
+
+`src/child.ts` holds what the call sites share:
+
+- **`exitCode(child)`**: call it right after `spawn`. It settles on `exit`
+  (not `close`, which a daemonized grandchild can hold open), maps a signal to
+  `128 + signo` as a shell does, and rejects on a failed start. The rejection
+  is pre-caught so it is not reported as unhandled before the caller awaits it.
+- **`echo(stream, chunk)`**: writes and waits for `drain` when the buffer is
+  full, so echoing never outruns a slow reader.
+
+Tests use `spawnSync` for short commands.
+
+Other port details:
+
+- **`src/errors.ts`** `isNotFound` checks `ENOENT` (file) or `ESRCH` (process).
+- Temporary files are an exclusive `wx` create with mode `0600`.
+- `src/json.ts` holds type guards used instead of `as` casts on parsed JSON.
+- `process` and `Buffer` must come from `node:` imports:
+  `no-restricted-globals` in `scripts/project-lint.ts` enforces it
+  ([[lint-parity-never-shrinks]]).
+
+Related: how each agent CLI reports bad credentials is in
+[[agent-cli-auth-failures]].

.agents/memory/bot-agents-migration-decisions.md

@@ -1,5 +1,5 @@
 ---
-description: bot-agents migration decisions: live @main action for six repos, JSON profiles, Node 24.2+, Deno kept only for agents, no eslint-plugin-* packages needed
+description: bot-agents migration decisions: live @main action for six repos, JSON profiles, Node 24.2+, no eslint-plugin-* packages needed
 ---
 
 Decisions for `commons/bot-agents` (Capsulizers Gitea), from the Deno to
@@ -18,10 +18,6 @@ Node + Vite+ migration (PR #20, `node-migration`, 2026-10-15/16):
 - **Node 24.2+**, not 22: `src/post.ts` uses `import.meta.main`. There is no
   `engines` (user decision 2026-10-18): the `node:24-bookworm` job image
   decides the version ([[bot-agents-runtime-no-build]]).
-- **Deno stays in the action's global npm install** (`action.yml`), only
-  because the agents still check Deno-based consumer repos (memona,
-  memona-home). Remove it once those repos have moved; it is not a
-  dependency of this repo's TypeScript.
 - **No `eslint-plugin-*` packages** (`eslint-plugin-explicit-types`,
   `eslint-plugin-import-structure`, `eslint-plugin-lit-robust`; unscoped
   since 2026-10-18, formerly `@cunarist/...`). The Deno setup enabled no

.agents/memory/bot-agents-node-command-shim.md

@@ -1,25 +0,0 @@
----
-description: src/command.ts reproduces Deno.Command on child_process.spawn (stdio defaults, clearEnv, uid/gid, 128+signo); src/errors.ts maps NotFound to ENOENT/ESRCH
----
-
-The Deno code was ported one for one; two small modules keep the old shapes
-so callers barely changed:
-
-- **`src/command.ts`** wraps `child_process.spawn` with `Deno.Command`'s API:
-  `output()` and `spawn()`, `clearEnv`, `uid`/`gid` (the agent isolation runs
-  each profile as its own UID, 20000+), and Deno's stdio defaults: stdin
-  inherited; stdout/stderr piped for `output()`, inherited for `spawn()`. A
-  signal exit maps to status `128 + signo`. Status settles on process exit,
-  not on stream close. Use it instead of calling `node:child_process`
-  directly so isolation and status handling stay uniform.
-- **`src/errors.ts`** replaces `Deno.errors.NotFound` checks with an
-  `ENOENT`/`ESRCH` code check.
-- `makeTempFile` became an exclusive `wx` create with mode `0600`.
-- `src/json.ts` holds type guards used instead of `as` casts on parsed JSON.
-- `process` and `Buffer` must come from `node:` imports:
-  `no-restricted-globals` in `scripts/project-lint.ts` maps Deno's
-  `no-window`/`no-process-global`/`no-node-globals` there
-  ([[lint-parity-never-shrinks]]).
-
-Related: how each agent CLI reports bad credentials is in
-[[agent-cli-auth-failures]].

.agents/memory/bot-agents-tests-root-only.md

@@ -1,5 +1,5 @@
 ---
-description: Isolation and credential tests need root and use test.skipIf(!IS_ROOT); locally 5 skip, CI runs as root so all 61 run; verify isolation changes in node:24-bookworm as root
+description: Isolation and credential tests need root and use test.skipIf(!IS_ROOT); locally 5 skip, CI runs as root so all 66 run; verify isolation changes in node:24-bookworm as root
 ---
 
 Some tests exercise real UID isolation, process cleanup, and `prepare.ts`
@@ -7,10 +7,10 @@ credential cleanup. They need root and are written as
 `test.skipIf(!IS_ROOT)(...)` (`IS_ROOT` from `#testing`), so they show
 as skipped instead of silently passing.
 
-- As a normal user `vp test` passes 56 and skips 5. In CI (self-hosted
-  runner, root) all 61 run.
+- As a normal user `vp test` passes 61 and skips 5. In CI (self-hosted
+  runner, root) all 66 run.
 - When changing `isolation.ts`, `runtime.ts`, `credentials.ts`, `prepare.ts`,
-  or `command.ts`, run the suite as root in `node:24-bookworm` (e.g. a
+  or `child.ts`, run the suite as root in `node:24-bookworm` (e.g. a
   container with the repo mounted) before pushing; a green non-root run
   proves nothing about those paths.
 - The migration also ran an end-to-end smoke as root with fake