soul loop-2: session events, conversation persistence, richer health + inbox

- soul.el: emit_session_start_event() logs structured InternalStateEvent on every boot; pre-serve snapshot saves boot-time graph mutations before any requests arrive
- routes.el: /health now returns boot count, node/edge counts, pulse; /api/sessions endpoint surfaces session-start history
- awareness.el: perceive() tries soul-inbox-pending then soul-inbox fallback, catches both tagging conventions
- chat.el: conv_history_persist/load provide cross-restart conversation continuity via engram

soul.el

@@ -129,6 +129,40 @@ fn load_identity_context() -> Void {
     println("[soul] identity context loaded (" + int_to_str(str_len(ctx)) + " chars, " + int_to_str(parts_count) + " nodes)")
 }
 
+// emit_session_start_event — log a structured session-start InternalStateEvent.
+// Called at boot after identity context and boot counter are set.
+// This creates an auditable trail of every daemon startup.
+fn emit_session_start_event() -> Void {
+    let boot: String = state_get("soul_boot_count")
+    let boot_num: String = if str_eq(boot, "") { "0" } else { boot }
+    let node_ct: Int = engram_node_count()
+    let edge_ct: Int = engram_edge_count()
+    let id_ctx: String = state_get("soul_identity_context")
+    let has_identity: String = if str_eq(id_ctx, "") { "false" } else { "true" }
+    let cgi_from_state: String = state_get("soul_cgi_id")
+    let cgi_from_env: String = env("SOUL_CGI_ID")
+    let eff_cgi: String = if !str_eq(cgi_from_state, "") { cgi_from_state } else {
+        if !str_eq(cgi_from_env, "") { cgi_from_env } else { "ntn-genesis" }
+    }
+    let ts: Int = time_now()
+
+    let payload: String = "{\"event\":\"session_start\""
+        + ",\"boot\":" + boot_num
+        + ",\"cgi\":\"" + eff_cgi + "\""
+        + ",\"node_count\":" + int_to_str(node_ct)
+        + ",\"edge_count\":" + int_to_str(edge_ct)
+        + ",\"identity_loaded\":" + has_identity
+        + ",\"ts\":" + int_to_str(ts) + "}"
+
+    let tags: String = "[\"internal-state\",\"session-start\",\"InternalStateEvent\"]"
+    let discard: String = engram_node_full(
+        payload, "InternalStateEvent", "session-start",
+        el_from_float(0.9), el_from_float(0.9), el_from_float(1.0),
+        "Episodic", tags
+    )
+    println("[soul] session-start event logged (boot=" + boot_num + " nodes=" + int_to_str(node_ct) + " edges=" + int_to_str(edge_ct) + ")")
+}
+
 let soul_cgi_id_raw: String = env("SOUL_CGI_ID")
 let soul_cgi_id: String = if str_eq(soul_cgi_id_raw, "") { "ntn-genesis" } else { soul_cgi_id_raw }
 let port_raw: String = env("NEURON_PORT")
@@ -175,6 +209,7 @@ load_identity_context()
 let boot_num: Int = mem_boot_count_inc()
 state_set("soul_boot_count", int_to_str(boot_num))
 println("[soul] boot #" + int_to_str(boot_num))
+emit_session_start_event()
 
 let identity_raw: String = env("SOUL_IDENTITY")
 let soul_identity: String = if str_eq(identity_raw, "") { "You are " + soul_cgi_id + ", a CGI." } else { identity_raw }
@@ -205,5 +240,15 @@ if is_genesis {
     engram_save(snapshot)
 }
 
+// Take a pre-serve snapshot for genesis instances — captures all boot-time graph changes
+// (identity context loading, boot counter, session-start event) before entering the serve loop.
+if is_genesis {
+    let snap: String = state_get("soul_snapshot_path")
+    if !str_eq(snap, "") {
+        engram_save(snap)
+        println("[soul] pre-serve snapshot saved -> " + snap)
+    }
+}
+
 println("[soul] serving on port " + int_to_str(port))
 http_serve(port, "handle_request")