feat: el-ide — native IDE for engram-lang, LSP, type graph, plugin ecosystem

Axum HTTP server (port 7771) serving a single-page IDE with CodeMirror 6
syntax highlighting for engram-lang, a force-directed type graph visualizer,
LSP (completions, hover, diagnostics), SSE-streamed build/run output, a
plugin host with five first-party plugins, and a reasoning panel that proxies
to engram-server. 28 tests across three crates, zero warnings.

ide/crates/el-ide-server/src/sse.rs

@@ -0,0 +1,20 @@
+//! SSE helpers for streaming build/run output.
+
+use axum::response::sse::Event;
+
+/// Build a line-output SSE event, classifying the line as error/warning/success/info.
+pub fn classify_line(line: &str) -> Event {
+    let event_type = if line.to_lowercase().contains("error") {
+        "error"
+    } else if line.to_lowercase().contains("warning") || line.to_lowercase().contains("warn") {
+        "warning"
+    } else if line.to_lowercase().contains("compiled")
+        || line.to_lowercase().contains("ok")
+        || line.to_lowercase().contains("success")
+    {
+        "success"
+    } else {
+        "info"
+    };
+    Event::default().event(event_type).data(line.to_string())
+}