fix(format-v3): harden system binding against replay and bypass attacks (F-01, F-02, F-03)

- F-02: Require restore_nonce token and explicit confirmation (--rebuild-mac) for PendingRebuild
- F-01: Extend canonical MAC transcript to include chunk generation tuples (node_id, chunk_index, generation) and support transparent legacy migration
- F-03: Make V2-to-V3 container upgrade atomic with transactional rollback and dual-slot version update
- Bump version to 0.9.4 and update changelog and security docs

src/main.rs

@@ -117,6 +117,10 @@ enum Commands {
         /// Aktiviert den lautlosen Stealth-Modus (keine Banner, Pfade, URLs oder Fortschrittsausgaben)
         #[arg(short, long, default_value_t = false)]
         stealth: bool,
+
+        /// Autorisiert den Neuaufbau des Metadaten-MAC nach einem Header-Restore (F-02)
+        #[arg(long, default_value_t = false)]
+        rebuild_mac: bool,
     },
 
     /// Trennt ein eingebundenes Netzlaufwerk manuell
@@ -1626,6 +1630,7 @@ async fn run() -> Result<()> {
             no_anti_leak,
             anti_leak_list,
             stealth,
+            rebuild_mac,
         } => {
             let drive_char = match drive {
                 Some(ref d) => parse_drive_letter(d)?,
@@ -1679,6 +1684,7 @@ async fn run() -> Result<()> {
                 anti_leak,
                 anti_leak_list.as_deref(),
                 stealth,
+                rebuild_mac,
             )
             .await?;
         }