self-review 2026-06-10: fix ise_post JSON escaping + rebuild soul daemon

Two fixes:

1. ise_post was only escaping " in content strings. When wm_top contained
   node labels with \n (backslash-n escape sequences from jb_emit_escaped),
   the HTTP Engram server's JSON parser decoded \n as a literal newline in
   the stored content, making heartbeat ISEs unparseable. Fix: escape
   backslashes first, then quotes, then \n and \r — matching make_action's
   existing pattern. Result: heartbeat ISEs now parse cleanly.

2. Soul daemon (dist/neuron) was missing — the build command in the prompt
   was linking all 46 dist/*.c files together, causing 1092 duplicate symbol
   errors. EL compiles transitive imports inline so neuron.c is self-contained;
   correct build links ONLY neuron.c + el_runtime.c. Daemon now starts.

awareness.el

@@ -30,8 +30,16 @@ fn ise_post(content: String) -> Void {
         )
         return ""
     }
-    let safe: String = str_replace(content, "\"", "\\\"")
-    let body: String = "{\"content\":\"" + safe + "\"}"
+    // Proper JSON string escaping: backslashes first, then quotes, then control chars.
+    // Previously only escaped " — this caused ise_post to produce malformed JSON when
+    // content contained \n (backslash-n) from wm_top label escaping: the HTTP Engram
+    // server would decode \n as a literal newline in the stored content field, making
+    // the heartbeat ISE unparseable as JSON. (2026-06-10 self-review)
+    let safe1: String = str_replace(content, "\\", "\\\\")
+    let safe2: String = str_replace(safe1, "\"", "\\\"")
+    let safe3: String = str_replace(safe2, "\n", "\\n")
+    let safe4: String = str_replace(safe3, "\r", "\\r")
+    let body: String = "{\"content\":\"" + safe4 + "\"}"
     let discard: String = http_post_json(engram_url + "/api/neuron/state-events", body)
     return ""
 }