fix(calibration): register calibrated-presence-evidence schema via field_bridge

The new schema constant was defined and asserted as a raw string literal
directly in main.rs, which the semconv registry test scans and requires
every "ruview.*" literal there to be a registered attribute/event. This
isn't a tracing event, though -- it's a wire-schema tag structurally
identical to CALIBRATION_MODEL_RECEIPT_SCHEMA, which already lives in
field_bridge.rs specifically to stay out of that scan. Move the new
constant there and reference it by identifier from main.rs, matching the
existing precedent instead of hand-editing the generated semconv registry.

Co-Authored-By: claude-flow <ruv@ruv.net>

v2/crates/wifi-densepose-sensing-server/src/field_bridge.rs

@@ -19,6 +19,11 @@ use super::score_to_person_count;
 pub const CALIBRATION_MODEL_RECEIPT_SCHEMA: &str =
     "ruview.calibration.field-model-receipt.v1";
 
+/// Versioned schema for per-frame calibrated occupancy evidence bound to a
+/// model receipt, published on the sensing stream.
+pub const CALIBRATED_PRESENCE_EVIDENCE_SCHEMA: &str =
+    "ruview.calibration.calibrated-presence-evidence.v2";
+
 /// Length-only canonicalizer for calibration frames (issue #1170 pattern,
 /// shared with `multistatic_bridge`). Raw ESP32 amplitudes arrive at the
 /// hardware's native width (HT20 ≈ 64, HT40 ≈ 128/192); the FieldModel is

v2/crates/wifi-densepose-sensing-server/src/main.rs

@@ -419,9 +419,6 @@ struct CalibratedPresenceEvidence {
     person_count: usize,
 }
 
-const CALIBRATED_PRESENCE_EVIDENCE_SCHEMA: &str =
-    "ruview.calibration.calibrated-presence-evidence.v2";
-
 /// Sensing update broadcast to WebSocket clients
 #[derive(Debug, Clone, Serialize, Deserialize)]
 struct SensingUpdate {
@@ -2360,7 +2357,7 @@ impl AppStateInner {
             observed_at_unix_ms.saturating_mul(1_000),
         )?;
         Some(CalibratedPresenceEvidence {
-            schema: CALIBRATED_PRESENCE_EVIDENCE_SCHEMA.to_string(),
+            schema: field_bridge::CALIBRATED_PRESENCE_EVIDENCE_SCHEMA.to_string(),
             boot_epoch: receipt.boot_epoch.clone(),
             session_id: receipt.session_id.clone(),
             model_id: receipt.model_id.clone(),
@@ -2722,7 +2719,7 @@ mod calibration_expiry_tests {
 
         assert_eq!(
             evidence.schema,
-            "ruview.calibration.calibrated-presence-evidence.v2"
+            field_bridge::CALIBRATED_PRESENCE_EVIDENCE_SCHEMA
         );
         assert_eq!(evidence.boot_epoch, state.calibration_boot_epoch);
         assert_eq!(evidence.session_id, "cal-session-test");