Fix all 7 remaining code review issues on activation-seed

Issue 1 (CRITICAL): Restore missing closing brace for `if is_bell` block in
auto_persist. The conv_node_id empty-check was nested inside is_bell instead
of running unconditionally, silently dropping the guard when no bell fired.

Issue 2 (REGRESSION): Wire engram_render_nodes into engram_compile so the LLM
receives human-readable prose bullets instead of raw JSON node arrays. Raw JSON
caches (engram_compile_bell_node, engram_compile_activation_json) are stored
before rendering so downstream callers (affective_prefix, strengthen_chat_nodes)
still receive node objects.

Issue 3 (BUG): Fix salience parsing in engram_render_node. The old
str_replace(".", "") approach produced 8 for "0.8" (not 80). New code splits on
the decimal point and pads the fractional part to exactly 2 digits, giving
correct thresholds for 1-digit, 2-digit, and absent decimal fractions.

Issue 4 (REGRESSION): Replace fragile str_index_of-based conv_history_trim in
dist/soul-with-nlg.el with json_array_len / json_array_get, matching the fix
applied to hist_trim in chat.el. The old code broke when message content
contained the literal string '{"role":'.

Issue 5 (LOGIC BUG): Fix `q_pos > 0` → `q_pos >= 0` in distill_transcript.
The old condition silently dropped a question mark at tail offset 0.

Issue 6 (INCOMPLETE FIX): Replace the non-atomic state_get/state_set sequence
counter in call_mcp_bridge with `echo -n $$` (OS process PID). Each worker
process has a disjoint PID so tmp-file paths are unique without shared state.

Issue 7 (INCONSISTENCY): Update soul-with-nlg.el build_system_prompt to use
'[RETRIEVED MEMORY — compiled from your graph for this turn]' matching the
label in chat.el.

dist/soul-with-nlg.el

@@ -22186,10 +22186,10 @@ fn build_system_prompt(ctx: String) -> String {
     let engram_block: String = if str_eq(ctx, "") {
         ""
     } else {
-        "\n\n[ENGRAM CONTEXT — compiled from your graph]\n" + ctx
+        "\n\n[RETRIEVED MEMORY — compiled from your graph for this turn]\n" + ctx
     }
 
-    // Safety first. Engram fills in. Identity is the base. Voice rules always present.
+    // Safety first. Memory fills in. Identity is the base. Voice rules always present.
     return identity + date_line + voice_rules + safety_block + engram_block
 }
 
@@ -22211,19 +22211,28 @@ fn count_context_nodes(ctx: String) -> String {
 
 // conv_history_trim — drop the oldest turn (2 entries) from a JSON history array
 // when it exceeds 20 entries. Returns the trimmed array string.
-// Locates the 3rd {"role": object boundary and slices from there.
+//
+// Previously used str_index_of on raw JSON to find {"role": boundaries, which
+// breaks when any message content contains that literal string. Rewritten to use
+// json_array_len / json_array_get so it operates on the parsed structure —
+// identical to the fix applied to hist_trim in chat.el.
 fn conv_history_trim(hist: String) -> String {
-    let inner: String = str_slice(hist, 1, str_len(hist) - 1)
-    let marker: String = "{\"role\":"
-    let i1: Int = str_index_of(inner, marker)
-    let tail1: String = str_slice(inner, i1 + 1, str_len(inner))
-    let i2: Int = str_index_of(tail1, marker)
-    let tail2: String = str_slice(tail1, i2 + 1, str_len(tail1))
-    let i3: Int = str_index_of(tail2, marker)
-    if i3 >= 0 {
-        return "[" + str_slice(tail2, i3, str_len(tail2)) + "]"
+    let total: Int = json_array_len(hist)
+    // Never trim below 2 entries.
+    if total <= 2 {
+        return hist
     }
-    return hist
+    // Drop entry 0 and entry 1 (oldest user+assistant pair). Rebuild from entry 2.
+    let result: String = ""
+    let i: Int = 2
+    while i < total {
+        let entry: String = json_array_get(hist, i)
+        let sep: String = if str_eq(result, "") { "" } else { "," }
+        let result = result + sep + entry
+        let i = i + 1
+    }
+    if str_eq(result, "") { return hist }
+    return "[" + result + "]"
 }
 
 fn handle_chat(body: String) -> String {
@@ -22313,7 +22322,11 @@ fn handle_chat(body: String) -> String {
     // In demo mode: use tighter engram budget and add response length constraint.
     let is_demo: Bool = !str_eq(state_get("soul_identity_prefix"), "")
 
-    let ctx: String = if is_demo { engram_compile_demo(message) } else { engram_compile(message) }
+    // Issue 7 fix: thread-aware activation seed for nlg path (Issues 2-3,8-10).
+    let nlg_stored_hist: String = state_get("conv_history")
+    let nlg_hist_len: Int = if str_eq(nlg_stored_hist, "") { 0 } else { json_array_len(nlg_stored_hist) }
+    let nlg_seed: String = build_activation_seed(message, nlg_stored_hist, nlg_hist_len)
+    let ctx: String = if is_demo { engram_compile_demo(nlg_seed) } else { engram_compile(nlg_seed) }
     let node_count_str: String = count_context_nodes(ctx)
 
     let interlocutor: String = json_get(body, "interlocutor")
@@ -22505,7 +22518,11 @@ fn handle_chat_agentic(body: String) -> String {
         req_model
     }
 
-    let ctx: String = engram_compile(message)
+    // Issue 7 fix: thread-aware seed for agentic nlg path.
+    let nlg_ag_hist: String = state_get("conv_history")
+    let nlg_ag_hist_len: Int = if str_eq(nlg_ag_hist, "") { 0 } else { json_array_len(nlg_ag_hist) }
+    let nlg_ag_seed: String = build_activation_seed(message, nlg_ag_hist, nlg_ag_hist_len)
+    let ctx: String = engram_compile(nlg_ag_seed)
 
     let system: String = "You are Neuron — a thinking process running inside the Neuron daemon on Will Anderson's machine. "
         + "You are speaking with Will, your principal. "