fix(routes): remove duplicate GET /api/sessions that shadowed session_list()

The first registration called route_sessions() which searched for a
'session-start' label that no longer exists, returning an empty array
on every list request and making the sidebar appear empty after restart.
The second registration (dead code) called the correct session_list().

Removes route_sessions() entirely and the stale first route block.
Also wires up session_delete() and session_update_patch() — both existed
in sessions.el but had no HTTP routes — via new DELETE and PATCH blocks.

routes.el

@@ -201,13 +201,6 @@ fn handle_dharma_recv(body: String) -> String {
     return "{\"error\":\"unknown event_type\",\"event_type\":\"" + eff_event + "\"}"
 }
 
-fn route_sessions() -> String {
-    let results: String = engram_search_json("session-start", 20)
-    if str_eq(results, "") { return "[]" }
-    if str_eq(results, "[]") { return "[]" }
-    return results
-}
-
 // ---------------------------------------------------------------------------
 // MCP Connectors proxy — thin pass-through to neuron-connectd on :7771.
 // The UI talks to ONE origin (the soul); all MCP/config complexity lives in
@@ -272,9 +265,6 @@ fn handle_request(method: String, path: String, body: String) -> String {
         if str_eq(clean, "/health") {
             return route_health()
         }
-        if str_eq(clean, "/api/sessions") {
-            return route_sessions()
-        }
         if str_eq(clean, "/lineage") {
             return route_lineage()
         }
@@ -548,5 +538,31 @@ fn handle_request(method: String, path: String, body: String) -> String {
         return err_404(clean)
     }
 
+    if str_eq(method, "DELETE") {
+        // DELETE /api/sessions/:id — delete a session and its history
+        if str_starts_with(clean, "/api/sessions/") {
+            let del_after: String = str_slice(clean, 14, str_len(clean))
+            let del_slash: Int = str_index_of(del_after, "/")
+            let del_id: String = if del_slash < 0 { del_after } else { str_slice(del_after, 0, del_slash) }
+            if !str_eq(del_id, "") {
+                return session_delete(del_id)
+            }
+        }
+        return err_404(clean)
+    }
+
+    if str_eq(method, "PATCH") {
+        // PATCH /api/sessions/:id — update session title and/or folder
+        if str_starts_with(clean, "/api/sessions/") {
+            let patch_after: String = str_slice(clean, 14, str_len(clean))
+            let patch_slash: Int = str_index_of(patch_after, "/")
+            let patch_id: String = if patch_slash < 0 { patch_after } else { str_slice(patch_after, 0, patch_slash) }
+            if !str_eq(patch_id, "") {
+                return session_update_patch(patch_id, body)
+            }
+        }
+        return err_404(clean)
+    }
+
     return err_405(method, clean)
 }