Quests: restart resets variables, respawns giver and NPCs; final failures

Quest audit (docs/quest-audit.md, tools/questscript.mjs), fixes 2-8.
New mods/questscript.cpp scans the script code once (giver, own variables,
needed NPCs, QIS_OnEnter creations, story-ending failure labels).
questfail: generic, giverless, story-ending and NPC-gone failures stay
final; a restart restores the variables snapshot taken at Quest_Trigger,
deletes OnEnter leftovers, respawns the giver and needed NPCs and gives the
accept dialog back. questgiver slimmed on top of questscript.

Not yet tested in game.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tools/README.md

@@ -10,6 +10,7 @@ passed explicitly.
 | `find-imm.mjs <exe> /regex/` | every instruction whose text matches (e.g. `/96AB0h\]/`) |
 | `rtti.mjs <exe> <Class>` | vtables of an MSVC class via RTTI |
 | `decompile.ps1 <addr...>` | decompile from the persistent Ghidra project `ghidra/` |
+| `questscript.mjs <dir> <quest id...>` | decode a quest script folder (`bin\TYPE_NPC_<class>`, `bin\Addon\NetScriptCamp`): a quest's labels and where other labels use its NPCs/variables; `--list`, `--facts [ids]` (giver, death labels), `--label <name>`, `--grep <regex>` (matching instructions in all labels) |
 | `rename.ps1` | apply the function names in `names.txt` to the Ghidra project (add names there as functions are identified) |
 
 ## Persistent Ghidra project (`ghidra/`, not in git)