fix(recovery): resolve metadata MAC desync after recovery (R-NEW-1) & complete release workflow (CI-01)

- R-NEW-1: Recalculate metadata HMAC upon recovery-key restore and mark backup restores as PendingRebuild to rebuild transparently on first mount
- CI-01: Update release.yaml to compile both Windows x86_64 and Linux musl with pinned Zig 0.16.0 and cargo-zigbuild 0.23.4
- W-1: Implement statvfs quota determination on Unix via libc
- Add RELEASE_PROCESS.md documenting release architecture and steps
- Bump version to 0.9.2 across manifests, lockfile, docs, Scoop and WinGet

src/storage.rs

@@ -208,6 +208,18 @@ fn current_timestamp() -> u64 {
         .unwrap_or(0)
 }
 
+/// Status der Metadaten-MAC-Integritätsprüfung (K-01 / R-NEW-1).
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum MetadataMacStatus {
+    /// Metadaten-MAC ist vorhanden und stimmt mit den kanonischen Metadaten überein.
+    Valid,
+    /// Container-Header wurde frisch aus einem Backup restauriert (metadata_gen == 0 && metadata_mac IS NULL).
+    /// Der MAC muss beim Mounten transparent mit dem aktiven DEK neu aufgebaut werden.
+    PendingRebuild,
+    /// Metadaten-MAC fehlt (bei gen > 0) oder stimmt nicht mit den berechneten Daten überein (Manipulationsverdacht).
+    Invalid,
+}
+
 impl Database {
     /// Öffnet oder erstellt die Container-Datenbank und initialisiert die Pragmas.
     pub fn open<P: AsRef<Path>>(path: P) -> Result<Self> {
@@ -2316,6 +2328,15 @@ impl Database {
 
     /// Prüft die Integrität des Metadaten-MAC für einen spezifischen Slot (0: Decoy, 1: Hidden).
     pub fn verify_metadata_mac_for_slot(&self, slot_id: u32, dek: &[u8; 32]) -> Result<bool> {
+        Ok(self.verify_metadata_mac_status_for_slot(slot_id, dek)? == MetadataMacStatus::Valid)
+    }
+
+    /// Prüft den detaillierten Integritätsstatus des Metadaten-MAC für einen spezifischen Slot (R-NEW-1).
+    pub fn verify_metadata_mac_status_for_slot(
+        &self,
+        slot_id: u32,
+        dek: &[u8; 32],
+    ) -> Result<MetadataMacStatus> {
         let conn = self.conn();
         let meta_row: Option<(u32, Option<Vec<u8>>, u64)> = conn
             .query_row(
@@ -2326,19 +2347,24 @@ impl Database {
             .optional()?;
 
         let Some((version, mac_opt, gen)) = meta_row else {
-            return Ok(false);
+            return Ok(MetadataMacStatus::Invalid);
         };
 
         if version < FORMAT_VERSION_V3 {
-            return Ok(true);
+            return Ok(MetadataMacStatus::Valid);
+        }
+
+        // R-NEW-1: Frisch restaurierter Container (gen == 0 && mac_opt IS NULL)
+        if gen == 0 && mac_opt.is_none() {
+            return Ok(MetadataMacStatus::PendingRebuild);
         }
 
         let Some(mac_bytes) = mac_opt else {
-            return Ok(false);
+            return Ok(MetadataMacStatus::Invalid);
         };
 
         if mac_bytes.len() != 32 {
-            return Ok(false);
+            return Ok(MetadataMacStatus::Invalid);
         }
 
         let mut expected_mac = [0u8; 32];
@@ -2347,12 +2373,11 @@ impl Database {
 
         let canonical = self.canonical_nodes_bytes_for_vault(slot_id)?;
         let mac_key = derive_metadata_mac_key(dek);
-        Ok(verify_metadata_mac(
-            &mac_key,
-            gen,
-            &canonical,
-            &expected_mac,
-        ))
+        if verify_metadata_mac(&mac_key, gen, &canonical, &expected_mac) {
+            Ok(MetadataMacStatus::Valid)
+        } else {
+            Ok(MetadataMacStatus::Invalid)
+        }
     }
 
     /// Führt ein Upgrade des Containerformats auf Format V3 durch (Format V3 / K-01 & K-02).
@@ -2528,7 +2553,12 @@ impl Database {
                 kdf_params TEXT NOT NULL,
                 wrapped_dek BLOB NOT NULL,
                 header_nonce BLOB NOT NULL,
-                header_tag BLOB NOT NULL
+                header_tag BLOB NOT NULL,
+                metadata_mac BLOB,
+                metadata_gen INTEGER NOT NULL DEFAULT 0,
+                lock_pid INTEGER,
+                lock_host TEXT,
+                lock_time INTEGER
             );",
         )?;
 
@@ -2542,8 +2572,8 @@ impl Database {
                 }
                 let params_json = serde_json::to_string(&slot.kdf_params)?;
                 conn.execute(
-                    "INSERT INTO meta (slot_id, magic, version, kdf_salt, kdf_params, wrapped_dek, header_nonce, header_tag)
-                     VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8)",
+                    "INSERT INTO meta (slot_id, magic, version, kdf_salt, kdf_params, wrapped_dek, header_nonce, header_tag, metadata_mac, metadata_gen)
+                     VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, NULL, 0)",
                     params![
                         slot.slot_id,
                         MAGIC_BYTES.as_slice(),
@@ -2559,8 +2589,8 @@ impl Database {
         } else {
             let params_json = serde_json::to_string(&meta.kdf_params)?;
             conn.execute(
-                "INSERT INTO meta (slot_id, magic, version, kdf_salt, kdf_params, wrapped_dek, header_nonce, header_tag)
-                 VALUES (0, ?1, ?2, ?3, ?4, ?5, ?6, ?7)",
+                "INSERT INTO meta (slot_id, magic, version, kdf_salt, kdf_params, wrapped_dek, header_nonce, header_tag, metadata_mac, metadata_gen)
+                 VALUES (0, ?1, ?2, ?3, ?4, ?5, ?6, ?7, NULL, 0)",
                 params![
                     MAGIC_BYTES.as_slice(),
                     meta.version,
@@ -2578,8 +2608,8 @@ impl Database {
             let (dummy_dek, dummy_nonce, dummy_tag, dummy_salt) = generate_dummy_slot();
             let dummy_params_json = serde_json::to_string(&KdfParams::default())?;
             conn.execute(
-                "INSERT INTO meta (slot_id, magic, version, kdf_salt, kdf_params, wrapped_dek, header_nonce, header_tag)
-                 VALUES (1, ?1, ?2, ?3, ?4, ?5, ?6, ?7)",
+                "INSERT INTO meta (slot_id, magic, version, kdf_salt, kdf_params, wrapped_dek, header_nonce, header_tag, metadata_mac, metadata_gen)
+                 VALUES (1, ?1, ?2, ?3, ?4, ?5, ?6, ?7, NULL, 0)",
                 params![
                     MAGIC_BYTES.as_slice(),
                     FORMAT_VERSION,