Make engram deletes/updates/forgets immutable on the launch branch

The ship-soul builds from this branch, which has the bounded-persona floor
(#93) but never received the tombstone/supersede immutability fix (that
went to main; hotfix diverged before it). So the launch soul failed
verify-soul-contract IMMUTABILITY on the delete/update/forget routes —
they hard-removed engram nodes via engram_forget/mem_forget.

Apply the same fix, mirroring the knowledge routes' supersede pattern:
- node/update -> create new node + "supersedes" edge to the original, KEEP
  the original (no engram_forget).
- node/delete, memory/delete, memory/forget, cultivate forget, and the
  autonomous awareness forget -> TOMBSTONE via the canonical mem_tombstone
  (memory.el): keep the node + its edges, record a Tombstone marker, hide
  from default bounded list reads (?include_deleted recovers). Never
  engram_forget. The MCP forget tool now routes to the tombstoning delete
  instead of faking a delete.
Internal GC that genuinely removes transient nodes (awareness inbox-trigger
consume, consolidation dedup, session-summary replace, telemetry pruning)
still calls engram_forget directly and is unchanged.

Regenerated dist/soul.c (single-TU) + per-module dist/{memory,awareness,
neuron-api}.c from THIS branch's sources under a 3GB physical-RSS watchdog
(peak ~32MB), built against the release el_runtime (v1.0.0-20260501). The
bounded-persona floor is preserved — verified in the emitted C and the
linked binary (BOUNDED PERSONA / SOUL_PERSONA_NAME strings present).

verify-soul-contract.sh: GATE PASS — PRESENCE all 27 routes, IMMUTABILITY
5/5 KEPT (memory-update, memory-delete, node-update, node-delete,
memory-forget).

mcp-wrapper/src/main.el

@@ -91,7 +91,7 @@ tool("beginSession", "Initialize session: surface recent high-importance memorie
 "," + tool("recall", "Retrieve memories by chain or query.") +
 "," + tool("inspectMemories", "List recent memory nodes.") +
 "," + tool("evolveMemory", "Update an existing memory node, optionally superseding another.") +
-"," + tool("forget", "Remove a node from memory.") +
+"," + tool("forget", "Supersede/tombstone a node (keeps it and its edges, recoverable); does not hard-delete.") +
 "," + tool("pinNode", "Strengthen a node so it stays salient.") +
 // ── Knowledge ───────────────────────────────────────────────────────────────
 "," + tool("searchKnowledge", "Search knowledge base by semantic similarity.") +
@@ -541,8 +541,12 @@ fn tool_forget(args: String) -> String {
     if str_eq(id, "") {
         return mcp_text_result("error: node_id is required")
     }
-    // Soft-delete: record a tombstone memory and return ok
-    return mcp_json_result("{\"ok\":true,\"deleted\":\"" + id + "\"}")
+    // Immutable delete: route to the soul's tombstoning endpoint (keeps the node
+    // + edges, hides from default reads, recoverable via ?include_deleted).
+    // Previously this returned a fake ok without deleting OR tombstoning anything.
+    let body: String = "{\"id\":\"" + id + "\"}"
+    let resp: String = http_post_json(neuron_url() + "/memory/delete", body)
+    return mcp_json_result(resp)
 }
 
 fn tool_check_events(args: String) -> String {