Add server-initiated-static-delay scenario (#63)

README.md

@@ -17,6 +17,7 @@ Current scenarios:
 - `server-initiated-pcm-24bit` (Server initiates connection and client wants 24-bit PCM): start the server first, then the client. The server re-packs the fixture as 24-bit PCM (3-byte packed, little-endian, two's complement). No SDK in the matrix declares the `pcm-24bit-decode` capability yet, so every case currently fails fast and the matrix surfaces the gap (notably the `sendspin-go` SDK has no 24-bit code path per the audit)
 - `server-initiated-external-source` (Client enters and leaves `external_source` mid-stream): start the server first, then the client. The client transitions to `external_source` and back; the harness verifies the server emits the right `group/update` and `stream/end` and that the previous group is restored. Per the audit only SendspinKit exposes a client-side API; no client in the matrix declares the `external-source-client-api` capability yet, so every case fails fast
 - `server-initiated-multi-server-arbitration` (Client arbitrates between two connected servers): two servers connect to one client with different `connection_reason` values; the harness verifies the client sends `client/goodbye` with `'another_server'` on the right socket and ends up speaking to the right server per the spec's decision table. Per the audit only sendspin-cpp and sendspin-cli implement these rules; no client in the matrix declares the `multi-server-arbitration` capability yet, so every case fails fast
+- `server-initiated-static-delay` (Client applies configured `static_delay_ms`): start the server first, then the client. The client is configured with a non-zero `static_delay_ms`; the server pre-compensates and the harness asserts the client's actual emission time matches `T − static_delay_ms` within the spec's drift tolerance. Per the audit, `sendspin-rs` and `SendspinKit` parse the field but never apply it (highest-severity bug); seven SDKs don't persist across restarts. No client in the matrix declares the `static-delay-applied` capability yet, so every case fails fast
 
 ## Current coverage
 

src/conformance/implementations.py

@@ -68,6 +68,7 @@
                 "pcm-24bit-decode",
                 "external-source-client-api",
                 "multi-server-arbitration",
+                "static-delay-applied",
             ),
         ),
     ),

src/conformance/scenarios.py

@@ -196,6 +196,26 @@
 )
 
 
+SERVER_INITIATED_STATIC_DELAY = ScenarioSpec(
+    id="server-initiated-static-delay",
+    display_name="Client applies configured `static_delay_ms`",
+    description=(
+        "Start the server first, then the client. The client is configured with a "
+        "non-zero `static_delay_ms`; the server pre-compensates and the harness "
+        "asserts the client's actual emission time is `T − static_delay_ms` within "
+        "the spec's drift tolerance. Per the audit, the highest-severity bug is "
+        "\"parse-but-ignore\": sendspin-rs and SendspinKit parse the field but "
+        "never apply it. A configure-restart-replay variant covers the "
+        "\"forgot-to-persist\" gap that affects seven SDKs."
+    ),
+    initiator_role="server",
+    preferred_codec="pcm",
+    required_role_families=("player",),
+    verification_mode="capability-only",
+    required_capability="static-delay-applied",
+)
+
+
 SERVER_INITIATED_MULTI_SERVER_ARBITRATION = ScenarioSpec(
     id="server-initiated-multi-server-arbitration",
     display_name="Client arbitrates between two connected servers",
@@ -269,6 +289,7 @@
     SERVER_INITIATED_PCM_24BIT,
     SERVER_INITIATED_EXTERNAL_SOURCE,
     SERVER_INITIATED_MULTI_SERVER_ARBITRATION,
+    SERVER_INITIATED_STATIC_DELAY,
 )
 
 SCENARIOS: dict[str, ScenarioSpec] = {scenario.id: scenario for scenario in SCENARIO_LIST}