feat(ludic.telemetry): an event queue batched to a PostHog-shaped endpoint

Events are encoded once into lines held in memory; a batch is the first
lines joined, with the player id put in where a mark stood, POSTed on
Http's own thread every flush_ms or at flush_at events; a failure keeps
its lines and doubles the wait up to backoff_max; the queue is on disk
every save_ms and read back at the next start; off (the enabled port)
drops the request in flight, empties the queue and deletes the file; and
a run that may not send (can_send) keeps nothing. The player id is the
machine's own id (MachineGuid, IOPlatformUUID, /etc/machine-id) hashed
with the game's salt, else random; it lives in the game's id file beside
whatever else the game keeps there.

Ports: TelemetryWorld (can_send, enabled, now_ms, stamp) and
TelemetryTransport (send, poll, drop; unbound: Http). Config is a record
(host, key, path, lib, queue_file, id_file, id_salt, and the timings).
Facts: TELEMETRY_SENT, _FAILED, _ID. Not a System: it runs from a
launcher's first frame, before any world exists.

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

packages/ludic.telemetry/ident.ludic

@@ -0,0 +1,92 @@
+# ident.ludic - one player id per machine: the operating system's own id (Windows MachineGuid,
+# macOS IOPlatformUUID, Linux /etc/machine-id) hashed with the game's salt, else random
+var telemetry__proc: int = -1
+var telemetry__proc_out: string = ""
+var telemetry__proc_t0: int = 0
+var telemetry__rand_n: int = 0
+
+# n random bytes as hex. Crypto.random_hex reads /dev/urandom, which Windows lacks (zeros there),
+# so it is mixed with the clock and the process and hashed: distinct per start everywhere
+export function telemetry_random_hex(n: int) -> string {
+  telemetry__rand_n += 1
+  let seed = Crypto.random_hex(n) + "|" + `{Time.now()}|{Crypto.random_u32()}|{Os.pid()}|{telemetry__rand_n}`
+  return Crypto.sha256(seed)[0..n * 2]
+}
+
+# the id outright (a game with accounts of its own, a test); written to the id file
+export function telemetry_set_id(id: string) -> void {
+  telemetry__id = id
+  let path = telemetry__conf().id_file
+  if len(path) > 0 {
+    var v = telemetry__read_obj(path)
+    if v == null { v = Value.object() }
+    Value.put(v, "id", Value.str(id))
+    Fs.write_text(path, Json.encode(v))
+  }
+  telemetry__fact(TELEMETRY_ID, 0, 0, 0)
+}
+
+function telemetry__random_id() -> void { telemetry_set_id("r-" + telemetry_random_hex(16)) }
+
+function telemetry__from_machine(raw: string) -> void {
+  let salt = telemetry__conf().id_salt
+  telemetry_set_id("m-" + Crypto.sha256(salt + ":" + Text.lower(raw))[0..32])
+}
+
+function telemetry__id_begin() -> void {
+  if len(telemetry__conf().id_salt) == 0 {
+    telemetry__random_id()
+    return
+  }
+  let plat = Os.platform()
+  if plat == "linux" {
+    let m = Fs.read_text("/etc/machine-id")
+    if m != null and len(Text.trim(m)) > 0 { telemetry__from_machine(Text.trim(m)) } else { telemetry__random_id() }
+    return
+  }
+  telemetry__proc_out = telemetry__conf().id_scratch
+  if len(telemetry__proc_out) == 0 { telemetry__proc_out = Os.temp_dir() + "/ludic-telemetry-machine.txt" }
+  if Fs.exists(telemetry__proc_out) { Fs.remove(telemetry__proc_out) }
+  telemetry__proc = telemetry__spawn_machine(plat)
+  telemetry__proc_t0 = Time.now()
+  if telemetry__proc < 0 { telemetry__random_id() }
+}
+
+function telemetry__spawn_machine(plat: string) -> int {
+  let args = new []string
+  if plat == "windows" {
+    var root = "C:\\Windows"
+    if Os.has_env("SystemRoot") and len(Os.env("SystemRoot")) > 0 { root = Os.env("SystemRoot") }
+    let out = "'" + Text.replace(telemetry__proc_out, "'", "''") + "'"
+    push(args, "-NoProfile")
+    push(args, "-NonInteractive")
+    push(args, "-Command")
+    push(args, "(Get-ItemProperty -LiteralPath 'HKLM:\\SOFTWARE\\Microsoft\\Cryptography').MachineGuid | Out-File -Encoding ascii -LiteralPath " + out)
+    return Process.spawn(root + "\\System32\\WindowsPowerShell\\v1.0\\powershell.exe", args)
+  }
+  push(args, "-c")
+  push(args, "ioreg -rd1 -c IOPlatformExpertDevice | awk -F'\"' '/IOPlatformUUID/{print $4}' > '" + telemetry__proc_out + "'")
+  return Process.spawn("/bin/sh", args)
+}
+
+# the machine id, once the child has written it (ten seconds at most)
+function telemetry__id_tick() -> void {
+  if telemetry__proc < 0 { return }
+  let code = Process.poll(telemetry__proc)
+  if code < 0 {
+    if Time.now() - telemetry__proc_t0 > 10 {
+      Process.kill(telemetry__proc)
+      Process.free(telemetry__proc)
+      telemetry__proc = -1
+      telemetry__random_id()
+    }
+    return
+  }
+  Process.free(telemetry__proc)
+  telemetry__proc = -1
+  var raw = ""
+  let s = Fs.read_text(telemetry__proc_out)
+  if s != null { raw = Text.trim(s) }
+  if Fs.exists(telemetry__proc_out) { Fs.remove(telemetry__proc_out) }
+  if code == 0 and len(raw) >= 8 { telemetry__from_machine(raw) } else { telemetry__random_id() }
+}