Quest NPCs turn blue and stop facing the hero once their quest is done

A dialog's quest comes from the game's script labels ("Dialog:<name>",
quest at +0x48). When that quest is done and not in progress, IsQuestNpc
answers false (blue on the minimap) and the idle action's type check
skips the turn towards the hero.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

docs/quests.md

@@ -101,3 +101,53 @@ ShowCompleted`, default 1) and calls `cUI_Book::Rebuild` 0x6b1670 (thiscall,
 no arguments; keeps tab and page if the page still exists, else ours clamps
 it). Off leaves out solved entries (main and side) and areas whose quests are
 all known and solved; failed quests stay (restartable).
+
+## Quest NPCs after the quest (request 2026-10-25)
+
+Request: NPCs related to a quest are drawn white on the minimaps and turn
+towards the player; once their quest is finished they should be drawn blue
+and stop turning, like other NPCs. `src/mods/questnpc.cpp`.
+
+Measured:
+
+- The zoomed map view (0x6cc950, call at 0x6cec6b) draws a creature white
+  when `cCreature::IsQuestNpc` (0x54fa30) is true: creature flags +0x200 bit
+  0x100 / 0x200 (escorted NPCs, set by the quest manager 0x46ae54..), or a
+  dialog +0x245 in 1..59999 whose type (`cDialogManager::DialogType`
+  0x49a180, record +0x48 of the 0x50-byte records at manager 0xaaaf00
+  +0x755c, name at record +4) is below 50.
+- Some quests move their giver on to dialog 0 at the end
+  (`DLG_15074_START` type 10 → `_OFFEN` 126 → `_ZIEL` 11 → 0); many leave it
+  on the quest's dialog: `auftrag10`, `auftrag2411`, `AuftragEnde202`,
+  `auftrag303` kept their dialog with the quest done (flags 3, book entry
+  solved).
+- The turning, found with a hardware write watch (DR0) on the facing +0x70:
+  the idle action (`cCreature::IdleAction` 0x544700, Think's action 0
+  handler) turns every creature with a dialog +0x245 in 1..99999 towards the
+  local hero each Think step (0x546334..0x5463d5, `cCreature::SetDirection`
+  0x44df60 → 0x44ddc0), unless its type is of kind 4 in the type table
+  (`TypeTable_IsKind4` 0x4265c0, call at 0x546357) or object flag +0x14 bit 2
+  is set. So every NPC with a dialog turns, not only quest NPCs.
+
+- Script labels (vector 0xaa9688..0xaa968c, 0x54 bytes each; quest scripts
+  and dialog answers are indices into it, run by `Script_RunLabel` 0x46bd80):
+  name +0, the quest the label belongs to +0x48 (-1 none; the label only runs
+  once that quest is triggered, 0x46bf11). Each dialog has a label
+  `Dialog:<dialog name>` (logged 2026-10-25: `Dialog:rg1_goodie1_auftrag`
+  9004 Vermisstes Kind, the Aufgeregter Bauer; `Dialog:auftrag_wueste` 9000;
+  `Dialog:auftrag11a1` 1101; `Dialog:DLG_15003_ZIEL` 15003;
+  `Dialog:geschlossen101` none).
+
+The quest of a dialog is its label's quest (`game/engine/quests.h`, script
+labels), looked up by the dialog record's name; cached per dialog. A first
+version read the quest id from the numbers in the dialog's name; that missed
+dialogs without one (the Aufgeregter Bauer's `rg1_goodie1_auftrag`, user
+report 2026-10-25) and misread others (`auftrag11a1`). When that quest
+exists, is done (flag 0x2) and not in progress (0x4):
+
+- the hook on `IsQuestNpc` returns false (blue on the minimap);
+- the type check call at 0x546357 is redirected to a thunk that also answers
+  true, so the idle action skips the turn.
+
+Dialogs without a quest (healers, closed shops: `geschlossen101`,
+`heilen_global`) stay as the game has them.