v0.15.1: Backup page Részletek overhaul with per-drive tier sections

Replace Tároló section with collapsible Részletek containing 3 tiers:
- Tier 1: per-drive restic repo stats with storage labels
- Tier 2: cross-drive items grouped by destination, split by method
- Tier 3: remote backup placeholder
Restore UI now shows tier + drive labels in snapshot dropdown.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CHANGELOG.md

@@ -1,5 +1,22 @@
 ## Changelog
 
+### What was just completed (2026-02-19 session 51)
+- **v0.15.1 — Backup Page "Részletek" Overhaul:**
+
+  Replaced the "Tároló" section on the backup page with a new "Részletek" section containing 3 collapsible tier sections with per-drive breakdowns.
+
+  **Tier 1 (Helyi mentés):** Shows per-drive restic repo stats (size, snapshot count) with storage labels. Includes aggregated totals when multiple drives exist, plus DB dump summary, integrity check, and encryption key (all carried over).
+
+  **Tier 2 (Másodlagos másolat):** Groups cross-drive backup items by destination drive, separated into restic and rsync method sections with per-app sizes.
+
+  **Tier 3 (Távoli mentés):** Placeholder for future B2/S3/SFTP remote backup.
+
+  **Restore UI improvements:** Snapshot dropdown now groups by tier (optgroup), shows tier label + drive name per snapshot (e.g., "1. szint, hdd_1"), and marks Tier 1 as recommended. Also lists Tier 2 (secondary restic) snapshots for visibility.
+
+  **Backend:** New `DriveRepoInfo` struct, `perDriveRepoStats()` method, `ListAllSnapshots()` that includes secondary restic repos, and `Tier2DriveGroup` handler struct. `SnapshotInfo` now carries `Tier` and `DriveLabel` fields.
+
+  **Files modified (5):** `internal/backup/backup.go`, `internal/backup/restic.go`, `internal/web/handlers.go`, `internal/api/router.go`, `internal/web/templates/backups.html`, `internal/web/templates/style.css`
+
 ### What was just completed (2026-02-18 session 50)
 - **v0.15.0 — Attach Existing Drive (bind mount wizard):**