feat(board): add readable physical board signs

knowledge/log.md

@@ -91,3 +91,10 @@ description: Chronological record of material decisions affecting Spigot Quest B
 - Registered all visible planks and signs in one durable operation and added obstruction checks plus block rollback when construction or persistence fails.
 - Preserved existing single-block board creation and persisted board compatibility.
 - Verified 103 tests and the plugin JAR with `./gradlew clean check jar`.
+
+## 2026-09-05 — Readable physical-board signage
+
+- Added centered `Quest Board` and right-click instruction signs on the two layers above each generated board's three decorative signs.
+- Registered all five signs and the plank face as shared-board interaction locations.
+- Added exact legacy-structure detection and failure-safe startup upgrades for previously generated three-sign boards without touching custom or altered structures.
+- Verified 111 tests and the plugin JAR with `./gradlew clean check jar`.

knowledge/user-stories/index.md

@@ -16,3 +16,4 @@ description: Catalog of user stories for the Spigot Quest Board plugin.
 8. [US-008: Control player quest commands](us-008-control-player-quest-commands.md)
 9. [US-009: Use a screen-fitting quest-board interface](us-009-use-a-screen-fitting-quest-board-interface.md)
 10. [US-010: Generate a physical quest-board structure](us-010-generate-a-physical-quest-board.md)
+11. [US-011: Add readable physical-board signage](us-011-add-readable-physical-board-signage.md)

knowledge/user-stories/us-011-add-readable-physical-board-signage.md

@@ -0,0 +1,26 @@
+---
+type: User Story
+title: "US-011: Add readable physical-board signage"
+description: Give generated quest boards a readable title and browsing instruction above their decorative signs.
+status: done
+---
+
+# US-011: Add readable physical-board signage
+
+As a **player**, I want readable signs on a generated quest board so that I know what it is and how to open it.
+
+## Acceptance criteria
+
+- [x] A generated physical board has a centered top sign reading `Quest Board` across its sign lines.
+- [x] A centered sign immediately below instructs the player to right-click a sign below to browse quests.
+- [x] The existing lower row retains three decorative signs with obfuscated or gibberish text.
+- [x] All five signs and the visible oak planks open the globally shared quest-board interface.
+- [x] New physical boards reserve and validate space for all five signs without overwriting blocks.
+- [x] Existing generated boards with the prior three-sign layout are detected from their exact registered oak structure and upgraded with the two centered readable signs.
+- [x] Existing custom single-block boards and unrelated structures are not modified.
+- [x] Existing-board upgrades never overwrite occupied sign locations and persist new interaction locations failure-safely.
+- [x] Automated tests verify sign placement, readable text, decorative text, interaction registration, obstruction handling, and prior-layout migration.
+
+## Related
+
+- [US-010: Generate a physical quest-board structure](us-010-generate-a-physical-quest-board.md)