fix(restart): skip dangling relations on memory index rebuild; prune on compaction

- Fix restart exit code 1 caused by missing relation targets after delete+rebuild
- memory_index_build: skip relations whose targets no longer exist
- store_rebuild / write_snapshot: prune dangling relations and sources
- Remove diagnostic fprintf from server.c and context.c
- Enable restart resume test in mcp_protocol_test.py
- Add scripts/benchmark_p1_cp.py and run 10k/50k import/export round-trip
- Mark P1-CP, P7-001, P7-CP complete in development-plan.md

1 files changed, 70 insertions, 2 deletions

diff --git a/src/storage/store.c b/src/storage/store.c
index 5701578..060c6f6 100644
--- a/src/storage/store.c
+++ b/src/storage/store.c
@@ -645,6 +645,72 @@ metadata_targets_valid(tiny_store_t *store, const char *self_id, const tiny_meta
   return true;
 }
 
+static bool
+prune_metadata_references(tiny_store_t *store, tiny_message_t *message)
+{
+  size_t index, write_index;
+  bool changed = false;
+  if (!store || !message)
+    {
+      return false;
+    }
+  /* Prune relations whose targets are deleted or missing. */
+  for (index = 0, write_index = 0; index < message->metadata.relation_count; ++index)
+    {
+      tiny_store_entry_t *target = find_entry(store, message->metadata.relations[index].message_id);
+      if (target && !target->deleted)
+        {
+          if (write_index != index)
+            {
+              message->metadata.relations[write_index] = message->metadata.relations[index];
+            }
+          write_index++;
+        }
+      else
+        {
+          changed = true;
+        }
+    }
+  if (changed)
+    {
+      message->metadata.relation_count = write_index;
+      if (write_index == 0)
+        {
+          free(message->metadata.relations);
+          message->metadata.relations = NULL;
+        }
+    }
+  /* Prune sources whose targets are deleted or missing. */
+  changed = false;
+  for (index = 0, write_index = 0; index < message->metadata.source_count; ++index)
+    {
+      tiny_store_entry_t *target = find_entry(store, message->metadata.source_message_ids[index]);
+      if (target && !target->deleted)
+        {
+          if (write_index != index)
+            {
+              message->metadata.source_message_ids[write_index]
+                  = message->metadata.source_message_ids[index];
+            }
+          write_index++;
+        }
+      else
+        {
+          changed = true;
+        }
+    }
+  if (changed)
+    {
+      message->metadata.source_count = write_index;
+      if (write_index == 0)
+        {
+          free(message->metadata.source_message_ids);
+          message->metadata.source_message_ids = NULL;
+        }
+    }
+  return true;
+}
+
 static tiny_store_status_t
 prepare_update(tiny_store_t *store,
                tiny_store_entry_t *entry,
@@ -1262,7 +1328,8 @@ write_snapshot(tiny_store_t *store)
     {
       unsigned char prefix[16], *payload = NULL;
       uint32_t length = 0;
-      if (!serialize_put(&store->entries[index].message, &payload, &length))
+      if (!prune_metadata_references(store, &store->entries[index].message)
+          || !serialize_put(&store->entries[index].message, &payload, &length))
         {
           ok = false;
           break;
@@ -1773,7 +1840,8 @@ tiny_store_rebuild(tiny_store_t *store, tiny_rebuild_report_t *report)
         {
           unsigned char *payload = NULL;
           uint32_t length = 0;
-          if (!serialize_put(&store->entries[read_index].message, &payload, &length))
+          if (!prune_metadata_references(store, &store->entries[read_index].message)
+              || !serialize_put(&store->entries[read_index].message, &payload, &length))
             {
               status = TINY_STORE_NO_MEMORY;
               break;