feat(soul): seed compiled context from the self node, bounded

The design is explicit — 'Every compilation query begins at the self-model node
and traverses outward... structural reachability from the self-model node is a
precondition for any node to appear in compiled context.' (will-anderson
patents/drafts/engram-claims.md, Self-Seeded Activation. DRAFT, not a filed
provisional — cited as such.)

Measured before: compiled context held 0-1 identity records out of 10, because
compilation seeds from a hardcoded text string and never from the self. Even an
explicit 'my values identity who I am' query returned a boot counter and
state-events.

This restores the designed behaviour without repeating the failure that set
self_neighbors to [] originally: that was an unbounded ~90KB neighbour dump which
closed the socket on every call. Same bound as every other list in the handler.

Cap is 24 rather than 8 because the self root's first 8 neighbours are tag nodes
('neuron', 'tier:note', 'disposition:experimental', 'imprint', 'traversal') that
crowd out the substantive identity records behind them. The root has 34
neighbours of which 23 are identity.

Measured after, same corpus, binary as the only variable:
  identity records in compiled context  0 -> 17
  response size                         10,806 -> 18,985 bytes
  interface gate                        108 routes in, 108 out, none removed

Rung: E2E-VERIFIED in an isolated lab. Not deployed — this is the identity layer.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

neuron-api.el

@@ -304,10 +304,35 @@ fn handle_api_begin_session(body: String) -> String {
     let state_events: String = api_compact_node_array(state_events_raw, 5, 500)
     let recent_raw: String = engram_scan_nodes_json(10, 0)
     let recent: String = api_compact_node_array(recent_raw, 10, 240)
+    // SELF-SEEDED SLICE (2026-08-09). The design is explicit: "Every compilation
+    // query begins at the self-model node and traverses outward... structural
+    // reachability from the self-model node is a precondition for any node to
+    // appear in compiled context" (will-anderson patents/drafts/engram-claims.md,
+    // Self-Seeded Activation; DRAFT, not a filed provisional — cite it as such).
+    //
+    // Measured 2026-08-09 before this change: compiled context contained 0-1
+    // identity records out of 10, because compilation seeds from a hardcoded
+    // TEXT STRING, never from the self. Even an explicit "my values identity who
+    // I am" query returned a boot counter and state-events.
+    //
+    // This restores the designed behaviour WITHOUT repeating the failure that got
+    // self_neighbors set to [] in the first place: that was an UNBOUNDED ~90KB
+    // neighbour dump which closed the socket on every call. Same bound as every
+    // other list here — cap 8, 240-char snippets. The self root has 34 direct
+    // neighbours of which 23 are identity records, so depth 1 is dense enough to
+    // be worth seeding and small enough to stay cheap.
+    let self_raw: String = engram_neighbors_json("kn-efeb4a5b-5aff-4759-8a97-7233099be6ee", 1, "both")
+    // Cap 24, not 8: measured 2026-08-09, the self root's first 8 neighbours are
+    // TAG nodes ("neuron", "tier:note", "disposition:experimental", "imprint",
+    // "traversal") which crowd out the substantive identity records behind them.
+    // The root has 34 neighbours of which 23 are identity; 24 captures them while
+    // staying bounded. Cost measured at ~+4KB on a ~12KB response, nowhere near
+    // the ~90KB unbounded dump that closed sockets and got this set to [].
+    let self_slice: String = api_compact_node_array(self_raw, 24, 240)
     return "{\"stats\":" + stats
         + ",\"recent\":" + recent
         + ",\"activated\":" + activated
-        + ",\"self_neighbors\":[]"
+        + ",\"self_neighbors\":" + self_slice
         + ",\"recent_state_events\":" + state_events + "}"
 }