fix(savedata): guard against sub-minimum backup data in recovery

nullcomp's passthrough path returns non-cmp-header data as-is without
error, which is correct for old uncompressed saves. However, a corrupt
backup slot containing garbage shorter than the minimum save layout
(100 bytes) would pass Decompress() and then panic in
updateStructWithSaveData() with a slice-bounds error at the name field
read (offset 88–100).

Add a minSaveSize check after each backup decompresses; skip the slot
if the result is too small. Also document the campaign system and the
fix in CHANGELOG under Unreleased.

CHANGELOG.md

@@ -7,8 +7,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- Fixed backup recovery panic: `recoverFromBackups` now rejects decompressed backup data smaller than the minimum save layout size, preventing a slice-bounds panic when nullcomp passes through garbage bytes as "already decompressed" data ([#182](https://github.com/Mezeporta/Erupe/pull/182)).
+
 ### Added
 
+- Event Tent (campaign) system: code redemption, stamp tracking, reward claiming, and quest gating for special event quests, backed by 8 new database tables and seeded with community-researched live-game campaign data ([#182](https://github.com/Mezeporta/Erupe/pull/182), by stratick).
+- Database migration `0010_campaign` (campaigns, campaign_categories, campaign_category_links, campaign_rewards, campaign_rewards_claimed, campaign_state, campaign_codes, campaign_quest).
 - JSON Hunting Road config: `bin/rengoku_data.json` is now supported as a human-readable alternative to the opaque `rengoku_data.bin` — the server assembles and ECD-encrypts the binary at startup, with `.bin` used as a fallback ([#173](https://github.com/Mezeporta/Erupe/issues/173)).
 - JSON quest files: `.json` files in `bin/quests/` are now supported alongside `.bin` — the server tries `.bin` first (full backward compatibility), then compiles `.json` on the fly to the MHF binary wire format ([#160](https://github.com/Mezeporta/Erupe/issues/160)). Covers all binary sections: quest text (UTF-8 → Shift-JIS), all 12 objective types, monster spawns (large + minion), reward tables, supply box, loaded stages, rank requirements, variant flags, forced equipment, map sections, area transitions, coordinate mappings, map info, gathering points, gathering tables, and area facilities. A `ParseQuestBinary` reverse function allows existing `.bin` files to be inspected and exported to JSON.
 

server/channelserver/handlers_character.go

@@ -114,6 +114,19 @@ func recoverFromBackups(s *Session, base *CharacterSaveData, charID uint32) (*Ch
 			continue
 		}
 
+		// nullcomp passes through data without a "cmp" header as-is (legitimate for
+		// old uncompressed saves). Guard against garbage data that is too small to
+		// contain the minimum save layout (name field at offset 88–100).
+		const minSaveSize = saveFieldNameOffset + saveFieldNameLen
+		if len(candidate.decompSave) < minSaveSize {
+			s.logger.Warn("Backup slot data too small after decompression, skipping",
+				zap.Uint32("charID", charID),
+				zap.Int("slot", backup.Slot),
+				zap.Int("size", len(candidate.decompSave)),
+			)
+			continue
+		}
+
 		s.logger.Warn("Savedata recovered from backup — primary was corrupt",
 			zap.Uint32("charID", charID),
 			zap.Int("slot", backup.Slot),