fix(lotw): precise uploaded marking; surface skipped/unavailable counts

P2 — markUploaded now only marks the records that actually made it
into the accepted TQ8 batch (preview.submittedIds), never the whole
candidate list. Previously, un-signable records skipped by prepare()
were still marked UP after any accepted upload, falsely showing them
as uploaded.

P4 — surface why records did not upload:
- When audit finds nothing pending, distinguish unavailable records
  (invalid call/date — check logbook) from unknown-result records
  (not retried automatically) instead of a blanket 'no pending'.
- Upload preview dialogs (Log tab + logbook) show a breakdown line:
  N already uploaded/duplicate · N unknown result · N un-uploadable.

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/repository/ILoTWUploadRepository.kt

@@ -66,7 +66,12 @@ data class LoTWUploadPreview(
     val firstUtc: String,
     val lastUtc: String,
     val contacts: List<String>,
-    val unknownSkipped: Int = 0
+    val unknownSkipped: Int = 0,
+    /** Un-signable records (invalid call/date/…) skipped instead of aborting the batch. */
+    val unavailableSkipped: Int = 0,
+    /** Ids of the records that actually made it into this TQ8 batch. Only these
+     *  may be marked "uploaded" after an accepted POST — never the full candidate list. */
+    val submittedIds: List<Long> = emptyList()
 )
 
 /** Local comparison against downloaded LoTW receipt flags and this app's durable upload receipts. */