feat(P1-002): add offline JSONL import via import_messages MCP tool

- implement `import_messages` MCP tool parsing manifest + PUT/DEL JSONL
- atomic store replacement under lock with overwrite/reject conflict policies
- add `include_deleted` to read_messages export view for full round-trip
- register new tool in MCP registry and update protocol test expectations
- update docs/development-plan.md and docs/implementation-status.md

Debug/Release/ASan 15/15 CTest pass

1 files changed, 19 insertions, 0 deletions

diff --git a/src/storage/store.h b/src/storage/store.h
index 3ddd24d..adeae35 100644
--- a/src/storage/store.h
+++ b/src/storage/store.h
@@ -77,7 +77,26 @@ tiny_store_status_t tiny_store_update(tiny_store_t *store,
                                       const tiny_message_patch_t *patch,
                                       tiny_message_t *updated,
                                       bool *changed);
+
+typedef enum tiny_import_policy
+{
+  TINY_IMPORT_OVERWRITE = 0,
+  TINY_IMPORT_REJECT
+} tiny_import_policy_t;
+
+typedef struct tiny_import_record
+{
+  bool deleted;
+  tiny_message_t message;
+} tiny_import_record_t;
+
 tiny_store_status_t tiny_store_rebuild(tiny_store_t *store, tiny_rebuild_report_t *report);
+tiny_store_status_t tiny_store_import(tiny_store_t *store,
+                                      const tiny_import_record_t *records,
+                                      size_t record_count,
+                                      tiny_import_policy_t policy,
+                                      size_t *imported_count,
+                                      size_t *rejected_count);
 void tiny_store_health(const tiny_store_t *store, tiny_store_health_t *health);
 
 size_t tiny_store_entry_count(const tiny_store_t *store);