Add durable fake SMS service runner

Makefile

@@ -0,0 +1,8 @@
+IDRIC_SMS_REQUEST ?= idric-sms-request
+
+.PHONY: test
+
+test:
+	sh -n services/sms/idric_sms_service.sh
+	sh -n tests/sms_service_test.sh
+	IDRIC_SMS_REQUEST="$(IDRIC_SMS_REQUEST)" sh tests/sms_service_test.sh

README.md

@@ -15,3 +15,10 @@ git clone --recurse-submodules https://github.com/isomorphisms/grease.git
 ```
 
 Keeping the Oils-derived tree as a pinned submodule avoids copying the full upstream repository while giving Grease one stable, reproducible source location for CI and local builds.
+
+## Service glue
+
+Filesystem-oriented service runners live under `services/`.  The first one is
+the [inspectable SMS service](services/sms/README.md): deterministic Idriç
+request parsing, durable one-time reminders, explicit consent provenance,
+`CANCEL`/`STOP`, and a fake outbox.

services/sms/README.md

@@ -0,0 +1,59 @@
+# Inspectable SMS service state
+
+This is the first filesystem service runner for `Network.SMS` in Idric-Net.  It
+uses the compiled `idric-sms-request` program for deterministic request parsing
+and a fake outbox for transport.  It does not contain a language model or a
+provider API.
+
+The first runner uses UTC deliberately.  A transport supplies a trusted
+telephone address, receive time, and unique inbound message id:
+
+```sh
+idric_sms_service.sh init ./state
+idric_sms_service.sh inbound ./state +15550000001 \
+  2026-09-01T14:00:00Z in_000001 'REMIND 15:00'
+idric_sms_service.sh run_due ./state 2026-09-01T15:00:00Z
+```
+
+The receipt is:
+
+```text
+scheduled evt_in_000001 2026-09-01T15:00:00Z
+sent evt_in_000001
+```
+
+and `state/fake_outbox/fake_evt_in_000001/body` contains `hey`.
+
+## State transitions
+
+```text
+inbound/<inbound-id>/             trusted envelope plus original body
+addresses/<telephone-address>     address-to-principal lookup
+principals/<principal-id>/        unprivileged correspondent and addresses
+consent/<event-id>/               exact authorization provenance
+scheduled/<instant>/<event-id>/   durable pending event
+sent/<event-id>/                  event moved here after fake delivery
+cancelled/<event-id>/             event moved here by CANCEL or STOP
+fake_outbox/<receipt>/             inspectable provider-independent delivery
+opt_out/<principal-id>             durable STOP state
+```
+
+Creating a reminder creates directories and small ordinary files.  Firing or
+cancelling it is an atomic `mv` out of `scheduled/`.  `STOP` creates an opt-out
+marker and moves every pending event for that principal to `cancelled/`.
+Possession of an address record never grants blanket permission: every outbound
+event names one record under `consent/`, including the principal, destination,
+request time, inbound id, original request, scheduled time, and message.
+
+The unknown-caller path creates a `public_correspondent`, not a Unix account and
+not a privileged Idriç principal.  An explicit later enrollment mechanism may
+promote or link principals without treating a telephone number as permanent
+identity.
+
+## Boundary
+
+The Grease runner owns filesystem transitions and invocation.  Idric-Net owns
+telephone, principal, message, request, authorization, and transport meanings.
+The fake outbox is permanent diagnostic infrastructure.  A future provider,
+GSM-modem, or Android adapter should consume the same outbound event rather than
+changing the scheduler's state model.