v0.5.0-beta: merge-with-key import, prior_author provenance, beta versioning

Merge-with-key: decrypt exported posts using original identity seed, re-create
under current identity with prior_author in BlobHeader for provenance tracking.
Download page restructured with stable (v0.4.4) + beta (v0.5.0-beta) sections.
Version bumped across all crates.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

crates/tauri-app/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "itsgoin-desktop"
-version = "0.4.4"
+version = "0.5.0"
 edition = "2021"
 
 [lib]

crates/tauri-app/src/lib.rs

@@ -2216,6 +2216,24 @@ async fn import_as_new_identity(
     Ok(format!("Identity {} imported — switch to it in Settings", &node_id[..12]))
 }
 
+#[tauri::command]
+async fn import_merge_with_key(
+    state: State<'_, AppNode>,
+    zip_path: String,
+    key_hex: String,
+) -> Result<String, String> {
+    let node = get_node(&state).await;
+    let result = itsgoin_core::import::merge_with_key(
+        std::path::Path::new(&zip_path),
+        &key_hex,
+        &node.storage,
+        &node.blob_store,
+        &node.node_id,
+        &node.secret_seed(),
+    ).await.map_err(|e| e.to_string())?;
+    Ok(result.message)
+}
+
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
 pub fn run() {
     tracing_subscriber::fmt()
@@ -2408,6 +2426,7 @@ pub fn run() {
             import_summary,
             import_public_posts,
             import_as_new_identity,
+            import_merge_with_key,
         ])
         .build(tauri::generate_context!())
         .expect("error while building tauri application")

crates/tauri-app/tauri.conf.json

@@ -1,6 +1,6 @@
 {
   "productName": "itsgoin",
-  "version": "0.4.4",
+  "version": "0.5.0",
   "identifier": "com.itsgoin.app",
   "build": {
     "frontendDist": "../../frontend",