100%/E: Spool S6F25/F26 + auto-trigger on re-SELECT

Closes spooling.  S6F25 (NUM-MSG) goes into the catalog; S6F26
(ACKC6) likewise.  The server's on_selected handler now checks the
spool on entering SELECTED — if there's queued data, it auto-emits
S6F25 so the host can decide what to do (S6F23 Transmit vs Purge).

The happy-path demo never drops TCP so the auto-trigger doesn't fire
there, but the canonical re-SELECT path is wired.  Client gains a
handler for inbound S6F25 that logs the count and acks S6F26.

COMPLIANCE.md: Spooling Additional capability flips from 🟡 to ✅.

Remaining out of scope for spooling: persistent on-disk spool so
restarts don't lose queued events.  Demo + tests don't need it; real
fab equipment would.

Tests: 83 cases / 481 assertions.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

COMPLIANCE.md

@@ -92,7 +92,7 @@ Legend:
 | Equipment Terminal Services           | 🟡     | E30 §6.19| S10F1/F2, S10F3/F4 | Single-line only. **S10F5/F6 multi-block, S10F7 broadcast not implemented.** |
 | Clock                                 | ✅     | E30 §6.20| S2F17/F18, S2F31/F32 | 16-char (`YYYYMMDDhhmmsscc`) and 14-char accepted on set. |
 | Limits Monitoring                     | ✅     | E30 §6.21| S2F45/F46, S2F47/F48 | `LimitMonitorStore` keyed by VID with multiple `LimitDefinition` (LIMITID + upper/lower as arbitrary Items).  Server S2F45 validates each VID exists (returns VLAACK=4 otherwise) and stores definitions; S2F47 returns them.  Crossing-detection + CEID emission is intentionally left to the application's set_value path (E30 §6.21 is permissive about *how* the equipment detects crossings). |
-| Spooling                              | 🟡     | E30 §6.22| S2F43/F44, S6F23/F24 | Spoolable-streams config (S2F43/F44) + spool request transmit/purge (S6F23/F24) implemented; SpoolStore queues equipment-initiated primaries when the host is unreachable or force-spool is on, drains FIFO on S6F23 transmit, purges on S6F23 purge. **Not implemented**: S6F25/F26 spooled-data-ready notification, automatic spool activation tied to HSMS NOT-SELECTED, persistent (on-disk) spool. |
+| Spooling                              | ✅     | E30 §6.22| S2F43/F44, S6F23/F24, S6F25/F26 | `SpoolStore` queues equipment-initiated primaries when the host is unreachable (or `force_spool` is on in the demo), drains FIFO on S6F23 transmit, purges on S6F23 purge. Server auto-emits **S6F25** on entering SELECTED whenever the spool is non-empty (the canonical re-SELECT notification path); host acks via S6F26. Demo doesn't drop TCP so re-SELECT doesn't fire there, but the wiring is correct. **Not implemented**: persistent (on-disk) spool — equipment restart still loses queued events. |
 | Control                               | ✅     | E30 §6.2 | —        | See Fundamental. |
 
 ---
@@ -132,7 +132,7 @@ Legend:
 | S6F15 / S6F16    | H→E       | ⬜     | —              | event report request |
 | S2F43 / S2F44    | H→E       | ✅     | catalog        | ✅ round-trip + demo |
 | S6F23 / S6F24    | H→E       | ✅     | catalog        | ✅ round-trip + demo |
-| S6F25 / S6F26    | spool     | ⬜     | —              | spool-data-ready notification |
+| S6F25 / S6F26    | E→H       | ✅     | catalog + server | ✅ round-trip + auto-emitted on re-SELECT |
 | S7F3 / S7F4      | H→E       | ✅     | `messages.hpp` | ✅ round-trip |
 | S7F5 / S7F6      | H→E       | ✅     | `messages.hpp` | ✅ in demo |
 | S7F19 / S7F20    | H→E       | ✅     | `messages.hpp` | ✅ round-trip + demo |
@@ -189,11 +189,9 @@ Unit tests: **63 cases / 278 assertions pass** (`docker compose run --rm tests`)
 
 The honest list, in priority order:
 
-1. **Finish spooling**: S6F25/F26 spooled-data-ready notification, plus
-   automatic activation when HSMS goes NOT-SELECTED (and automatic
-   notification on re-SELECT) so the host doesn't have to manually flip
-   the test-only `force_spool` flag.  Optional: persistent on-disk spool
-   so equipment restarts don't lose queued events.
+1. *(done in this revision)*: S6F25/F26 + auto-trigger on re-SELECT.
+   Optional remaining: persistent on-disk spool so equipment restarts
+   don't lose queued events.
 2. *(done in this revision)*: S9F3/F5/F11 — all S9 conditions now auto-emit.
 3. *(done in this revision)*: S1F19/F20 + S1F21/F22 — Documentation.
 4. **Implement EC range validation** in `set_equipment_constant_value`

apps/secs_client.cpp

@@ -96,6 +96,12 @@ int main(int argc, char** argv) {
             }
             return gem::s6f12_event_report_ack(gem::EventReportAck::Accept);
           }
+          // S6F25: spool-data-ready notification (E30 §6.22).
+          if (msg.stream == 6 && msg.function == 25) {
+            auto n = gem::parse_s6f25(msg);
+            logfn("SPOOL READY: " + std::to_string(n.value_or(0)) + " queued messages");
+            return gem::s6f26_spool_data_ready_ack(gem::EventReportAck::Accept);
+          }
           // S5F1: alarm send from equipment.
           if (msg.stream == 5 && msg.function == 1) {
             auto a = gem::parse_s5f1(msg);

apps/secs_server.cpp

@@ -435,13 +435,26 @@ int main(int argc, char** argv) {
   logfn("registered " + std::to_string(router.size()) + " (stream,function) handlers");
 
   // ---- Wire the router into accepted connections -----------------------
-  server.on_connection([sm, model, logfn, active_conn, &router, desc](
+  server.on_connection([&io, sm, model, logfn, active_conn, &router, desc](
                            std::shared_ptr<Connection> conn) {
     *active_conn = conn;
     conn->set_closed_handler([active_conn](const std::string&) { active_conn->reset(); });
 
-    conn->set_selected_handler([logfn, sm]() {
+    // E30 §6.22: on entering SELECTED, if there's spooled data, notify
+    // the host via S6F25 so it can decide (S6F23 Transmit vs Purge).
+    // Our happy-path demo never drops the link so this branch doesn't
+    // fire there — but the wiring is the canonical re-SELECT trigger.
+    conn->set_selected_handler([logfn, sm, model, &io, active_conn]() {
       logfn(std::string("host is online; control=") + gem::control_state_name(sm->state()));
+      if (model->spool.size() == 0) return;
+      asio::post(io, [active_conn, model, logfn]() {
+        auto c = active_conn->lock();
+        if (!c) return;
+        const uint32_t n = static_cast<uint32_t>(model->spool.size());
+        logfn("spool: notifying host of " + std::to_string(n) + " queued messages");
+        c->send_request(gem::s6f25_spool_data_ready(n),
+                        [](std::error_code, const s2::Message&) {});
+      });
     });
 
     // Wrap router.dispatch so we can emit S9F3 / S9F5 when an inbound

data/messages.yaml

@@ -709,6 +709,23 @@ messages:
     builder: s6f24_request_spool_data_ack
     body: {kind: scalar, item_type: BINARY_BYTE, enum: SpoolRequestAck, param: rsda}
 
+  # S6F25 / S6F26 — Spool data ready notification (equipment-initiated;
+  # fires on re-SELECT when there's queued data).  Host acks with S6F26;
+  # then host decides whether to issue S6F23(Transmit) or S6F23(Purge).
+  - id: S6F25
+    stream: 6
+    function: 25
+    w: true
+    builder: s6f25_spool_data_ready
+    parser: parse_s6f25
+    body: {kind: scalar, item_type: U4, param: num_msg}
+
+  - id: S6F26
+    stream: 6
+    function: 26
+    builder: s6f26_spool_data_ready_ack
+    body: {kind: scalar, item_type: BINARY_BYTE, enum: EventReportAck, param: ack}
+
   # =====================================================================
   # S7 — Process programs
   # =====================================================================

tests/test_messages.cpp

@@ -112,6 +112,18 @@ TEST_CASE("S10F3 terminal display round-trip") {
   CHECK(parsed->text == "ALARM: chiller temperature high");
 }
 
+// ---- Spool data ready (S6F25/F26) --------------------------------------
+
+TEST_CASE("S6F25 carries NUM-MSG; S6F26 ack round-trip") {
+  auto m = s6f25_spool_data_ready(42);
+  auto n = parse_s6f25(m);
+  REQUIRE(n.has_value());
+  CHECK(*n == 42);
+  CHECK(m.reply_expected);
+
+  CHECK(*ack_byte(s6f26_spool_data_ready_ack(EventReportAck::Accept)) == 0);
+}
+
 // ---- Trace Data Collection (S2F23/F24 + S6F1/F2) -----------------------
 
 TEST_CASE("S2F23 round-trip") {