🛒 Merchant NPC personal goods

• Merchant NPCs (peddlers) in cities now carry personal goods: tap View Goods in dialogue to open their stock.
• Stock rotates daily: every in-game day (about 1 real minute) brings 4-6 new items, decided by each merchant's own "luck" — on the same day, every merchant sells something different.
• Each merchant sells you at most 3 items per day; the count resets the next day.
• Regulars get discounts: real purchases raise the merchant's affinity toward you; higher affinity means a bigger discount, up to 10% off at max affinity. Buy more, get familiar, pay less.
• Cultivators, guards and other NPCs don't sell goods; the trade button no longer appears in their dialogue.

🔧 Fixes

• NPC dialogue avatars: previously the NPC's avatar in chat messages could render as a broken image; it now displays properly and falls back to the first character of their name in the worst case — no more broken icons.
• The trade button: previously tapping "Trade" completed a "trade" without letting you pick anything; merchants now open their personal stock directly — what you see is what you buy. (Thanks to the player who reported this!)

📦 Save notes

• Saves gain a merchant purchase-counter field; old saves are patched automatically on load — no action needed, progress is unaffected.