feat(system): multipart backup import via SAF picker — replace path-based import (issue #786) (#839)

* feat(system): multipart backup import via SAF picker — replace path-based import (issue #786)

* fix(system): backup trigger sends required JSON body — 422 fix (BackupRequest contract)

* fix(system): backup download waits for async archive + saves to Downloads

* fix(system): curator min_idle_hours Double parse + single-flight backup download

* fix(system): stream backup download to Downloads — @Streaming + chunked MediaStore write (OOM fix)

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Co-authored-by: M57 <hy4ri@users.noreply.github.com>

app/src/main/java/com/m57/hermescontrol/data/model/ActionResponse.kt

@@ -12,3 +12,13 @@ data class ActionResponse(
     val uploaded_bytes: Long? = null,
     val update_command: String? = null,
 )
+
+/**
+ * Body for POST /api/ops/backup — the backend requires a JSON body
+ * (BackupRequest; `output` optional). Sending no body at all gets a 422.
+ * Empty object (default) matches the desktop's `{"output": ...}` contract.
+ */
+@Serializable
+data class BackupTriggerRequest(
+    val output: String? = null,
+)

app/src/main/java/com/m57/hermescontrol/data/model/CuratorResponse.kt

@@ -7,7 +7,9 @@ data class CuratorResponse(
     val paused: Boolean? = null,
     val interval_hours: Int? = null,
     val last_run_at: String? = null,
-    val min_idle_hours: Int? = null,
+    // Backend sends a float (e.g. 2.0) — Int here broke JSON parsing (logcat
+    // "Unexpected symbol '.' in numeric literal at path: $.min_idle_hours").
+    val min_idle_hours: Double? = null,
     val stale_after_days: Int? = null,
     val archive_after_days: Int? = null,
 )