rename crates/ to engrams/, bindings/ to receptors/

- crates/ → engrams/ (Rust engrams live here)
- bindings/ → receptors/ (cross-language access points into the graph)
- Cargo.toml workspace paths updated

engram/engrams/engram-server/src/routes/projection.rs

@@ -0,0 +1,121 @@
+/// Projection API routes.
+///
+/// POST /projections              — register a projection schema
+/// GET  /projections              — list all registered schemas
+/// POST /projections/{name}/query — run activation then project results
+/// GET  /projections/{name}/schema — get a schema definition
+use axum::{
+    extract::{Path, State},
+    http::StatusCode,
+    Json,
+};
+use engram_projection::{
+    engine::ProjectionEngine,
+    schema::{ProjectionResult, ProjectionSchema},
+};
+use serde::{Deserialize, Serialize};
+use std::sync::Arc;
+use uuid::Uuid;
+
+use crate::state::AppState;
+
+// ── POST /projections ─────────────────────────────────────────────────────────
+
+pub async fn register_projection(
+    State(state): State<Arc<AppState>>,
+    Json(schema): Json<ProjectionSchema>,
+) -> Result<StatusCode, StatusCode> {
+    let mut reg = state
+        .projection_registry
+        .lock()
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
+    reg.upsert(schema)
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
+    Ok(StatusCode::CREATED)
+}
+
+// ── GET /projections ──────────────────────────────────────────────────────────
+
+#[derive(Serialize)]
+pub struct ListProjectionsResponse {
+    pub schemas: Vec<ProjectionSchema>,
+}
+
+pub async fn list_projections(
+    State(state): State<Arc<AppState>>,
+) -> Result<Json<ListProjectionsResponse>, StatusCode> {
+    let reg = state
+        .projection_registry
+        .lock()
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
+    let schemas = reg.list().into_iter().cloned().collect();
+    Ok(Json(ListProjectionsResponse { schemas }))
+}
+
+// ── GET /projections/{name}/schema ────────────────────────────────────────────
+
+pub async fn get_projection_schema(
+    State(state): State<Arc<AppState>>,
+    Path(name): Path<String>,
+) -> Result<Json<ProjectionSchema>, StatusCode> {
+    let reg = state
+        .projection_registry
+        .lock()
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
+    match reg.get(&name) {
+        Ok(schema) => Ok(Json(schema.clone())),
+        Err(_) => Err(StatusCode::NOT_FOUND),
+    }
+}
+
+// ── POST /projections/{name}/query ────────────────────────────────────────────
+
+#[derive(Deserialize)]
+pub struct ProjectionQueryRequest {
+    /// Seed node IDs for spreading activation.
+    pub seeds: Vec<Uuid>,
+    /// Query embedding for spreading activation.
+    pub query_embedding: Vec<f32>,
+    #[serde(default = "default_depth")]
+    pub max_depth: u8,
+    #[serde(default = "default_limit")]
+    pub limit: usize,
+}
+
+fn default_depth() -> u8 {
+    3
+}
+fn default_limit() -> usize {
+    20
+}
+
+pub async fn query_projection(
+    State(state): State<Arc<AppState>>,
+    Path(name): Path<String>,
+    Json(req): Json<ProjectionQueryRequest>,
+) -> Result<Json<ProjectionResult>, StatusCode> {
+    // Load schema
+    let schema = {
+        let reg = state
+            .projection_registry
+            .lock()
+            .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
+        match reg.get(&name) {
+            Ok(s) => s.clone(),
+            Err(_) => return Err(StatusCode::NOT_FOUND),
+        }
+    };
+
+    // Run spreading activation
+    let activated = {
+        let db = state.db.lock().map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
+        db.activate(&req.seeds, &req.query_embedding, req.max_depth, req.limit)
+            .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?
+    };
+
+    // Apply projection
+    let result = ProjectionEngine::project(&schema, &activated)
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
+
+    Ok(Json(result))
+}