lembas remote: manage remote: without YAML; a running service follows it

`lembas remote list | add | remove | enable | disable | mode | terminal`, with
`--json` printing {enabled, roots, max_mode, terminal}, for LLeMbas Desktop.
Writes go through the global config writer and keep comments.

The device's limits are now live getters over the remote: block, re-read when
config.yaml's stat changes. `lembas service` links even with remote work off
or no roots: it says roots: [] and refuses every session, directory and
terminal, so the instance can tell "no folder allowed yet" from "not running".
When what the instance was told changes, the link re-dials once nothing is
working, so `lembas remote add` or `enable` takes effect without a restart.
Harness spec 1.0.1 documents both.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/remote.ts

@@ -0,0 +1,151 @@
+// `lembas remote`: the global `remote:` block — what a LLeMbas instance may ask of this machine over
+// the link — managed without editing YAML, for people and for programs (LLeMbas Desktop) alike.
+//
+//   lembas remote list [--json]                    what is in force, defaults applied
+//   lembas remote add <dir>… [--json]              allow remote sessions there (turns remote work on)
+//   lembas remote remove <dir>… [--json]           stop allowing them there
+//   lembas remote enable | disable [--json]        remote.enabled
+//   lembas remote mode <manual|edit|auto|plan>     remote.max_mode
+//   lembas remote terminal <on|off>                remote.terminal
+//
+// Every change goes through the global config writer, which keeps the file's comments. A running
+// `lembas service` reads the block again whenever it uses it, so a change applies to it within a few
+// seconds, no restart (acp/link.ts). --json prints one object: {enabled, roots, max_mode, terminal}.
+import { resolve } from "node:path"
+import { ConfigError } from "./config/load.ts"
+import { expandHome } from "./config/paths.ts"
+import { coveredBy, realOrResolved, remoteBlock, remoteState, rootFor, type RemoteState } from "./config/remote.ts"
+import { MODES, type Mode } from "./config/schema.ts"
+import { updateGlobalConfig } from "./config/write.ts"
+
+export const REMOTE_USAGE = `usage: lembas remote list | add <dir>… | remove <dir>… | enable | disable | mode <${MODES.join("|")}> | terminal <on|off>  [--json]`
+
+export interface Io {
+  out: (line: string) => void
+  err: (line: string) => void
+  cwd?: string
+}
+
+const stdio: Io = { out: (l) => console.log(l), err: (l) => process.stderr.write(`lembas: ${l}\n`) }
+
+function describe(s: RemoteState): string[] {
+  return [
+    `remote work: ${s.enabled ? "on" : "off"}`,
+    s.roots.length ? `roots:\n${s.roots.map((r) => `  ${r}`).join("\n")}` : "roots: (none: no directory accepts remote work)",
+    `max mode: ${s.max_mode}`,
+    `terminal: ${s.terminal ? "on" : "off"}`,
+  ]
+}
+
+/** Runs one `lembas remote …` command; the exit status. */
+export function remoteCommand(argv: string[], io: Io = stdio): number {
+  const json = argv.includes("--json")
+  const args = argv.filter((a) => a !== "--json")
+  const [sub = "list", ...rest] = args
+  const said: string[] = []
+  let wrote = false
+  const show = () => {
+    const s = remoteState(remoteBlock())
+    if (json) io.out(JSON.stringify(s))
+    else for (const l of [...said, ...describe(s), ...(wrote ? ["(a running lembas service applies this within seconds)"] : [])]) io.out(l)
+    return 0
+  }
+  let block
+  try {
+    block = remoteBlock({ strict: true })
+  } catch (e) {
+    if (e instanceof ConfigError) return io.err(e.message), 1
+    throw e
+  }
+  const write = (edits: [string[], unknown][]) => {
+    updateGlobalConfig(edits.map(([k, v]) => [["remote", ...k], v]))
+    wrote = true
+  }
+
+  if (sub === "list") {
+    if (rest.length) return io.err(REMOTE_USAGE), 2
+    return show()
+  }
+
+  if (sub === "add") {
+    if (!rest.length) return io.err("usage: lembas remote add <dir>…"), 2
+    const roots = [...(block.roots ?? [])]
+    const added: string[] = []
+    const bad: string[] = []
+    for (const dir of rest) {
+      const r = rootFor(dir, io.cwd)
+      if (typeof r !== "string") {
+        bad.push(r.error)
+        continue
+      }
+      const by = coveredBy(r, roots)
+      if (by) {
+        said.push(realOrResolved(by) === r ? `${r}: already a root` : `${r}: already covered by ${by}`)
+        continue
+      }
+      roots.push(r)
+      added.push(r)
+    }
+    // All or nothing: a program that asked for three directories never gets two of them.
+    if (bad.length) {
+      for (const b of bad) io.err(b)
+      return 1
+    }
+    const edits: [string[], unknown][] = []
+    if (added.length) {
+      edits.push([["roots"], roots])
+      for (const r of added) said.push(`added ${r}`)
+    }
+    if (block.enabled !== true) {
+      edits.push([["enabled"], true])
+      said.push("remote work is now on (remote.enabled)")
+    }
+    if (edits.length) write(edits)
+    return show()
+  }
+
+  if (sub === "remove") {
+    if (!rest.length) return io.err("usage: lembas remote remove <dir>…"), 2
+    const roots = block.roots ?? []
+    const gone = new Set<string>()
+    const bad: string[] = []
+    for (const dir of rest) {
+      const want = realOrResolved(resolve(io.cwd ?? process.cwd(), expandHome(dir)))
+      const match = roots.filter((r) => realOrResolved(r) === want)
+      if (!match.length) bad.push(`${dir}: not one of the remote roots${roots.length ? ` (${roots.join(", ")})` : ""}`)
+      for (const m of match) gone.add(m)
+    }
+    if (bad.length) {
+      for (const b of bad) io.err(b)
+      return 1
+    }
+    write([[["roots"], roots.filter((r) => !gone.has(r))]])
+    for (const r of gone) said.push(`removed ${r}`)
+    if (gone.size === roots.length && block.enabled === true) said.push("no roots are left: remote sessions cannot be opened anywhere until one is added")
+    return show()
+  }
+
+  if (sub === "enable" || sub === "disable") {
+    if (rest.length) return io.err(REMOTE_USAGE), 2
+    write([[["enabled"], sub === "enable"]])
+    if (sub === "enable" && !(block.roots ?? []).length) said.push("no roots yet: lembas remote add <dir> to say where remote sessions may work")
+    return show()
+  }
+
+  if (sub === "mode") {
+    const m = rest[0] as Mode | undefined
+    if (rest.length !== 1 || !(MODES as readonly string[]).includes(m!)) return io.err(`usage: lembas remote mode <${MODES.join("|")}>`), 2
+    write([[["max_mode"], m]])
+    return show()
+  }
+
+  if (sub === "terminal") {
+    const v = rest[0]
+    if (rest.length !== 1 || (v !== "on" && v !== "off")) return io.err("usage: lembas remote terminal <on|off>"), 2
+    write([[["terminal"], v === "on"]])
+    return show()
+  }
+
+  io.err(REMOTE_USAGE)
+  return 2
+}