Skills, auto-attack, aura and chain lightning rework, Esc, cache fix

- Skill bar: no art selection; slot 0 is the right-click art, keys 0-6 cast
  slots directly; cooldown labels in exact seconds; slot 0 set apart.
- Arts regenerate on their own (casting no longer refills the group).
- Auto-attack after targeting or casting at a hostile creature, at the speed
  of a held button.
- Auras can be recast while active (renew, no second visual).
- Blicke wie Klingen hits every enemy in range, physical, with life leech.
- Blitzschlag steers the game's own chain: 3 + level/5 hits, 1 + level/10
  chains, re-hits a lone enemy.
- Weapon sets: click selects, drag only from the selected set; the leftmost
  set is clickable (signed hit tests).
- Esc closes open windows before opening the game menu.
- HUD: standalone buttons and texts are centred.
- Record cache sized for widened views (town lag while walking).
- Shared game code: orders, fx events, text drawing, cooldowns, effects.

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

src/re/patch.h

@@ -20,6 +20,30 @@ bool PatchInstructionDword(uint32_t instruction, uint32_t from, uint32_t to);
 // Replace the byte `from` at `instruction + offset` (an imm8 or disp8) by `to`.
 bool PatchInstructionByte(uint32_t instruction, size_t offset, uint8_t from, uint8_t to);
 
+// Replace the code bytes `from` at `address` by `to` (same length), e.g. a
+// whole short instruction.
+bool ReplaceCode(uint32_t address, const void* from, const void* to, size_t size);
+
+// The `call rel32` at `instruction` (E8) calls `from`; make it call `to`.
+bool RedirectCall(uint32_t instruction, uint32_t from, const void* to);
+
+// The near conditional jump at `instruction` (0F 8x rel32) goes to `from`;
+// make it go to `to`.
+bool RedirectJcc(uint32_t instruction, uint32_t from, const void* to);
+
+// A code replacement, for tables.
+struct CodeReplacement {
+    uint32_t address;
+    uint8_t from[8];
+    uint8_t to[8];
+    uint8_t size;
+};
+int ReplaceAll(const CodeReplacement* replacements, size_t count);
+template <size_t N>
+int ReplaceAll(const CodeReplacement (&replacements)[N]) {
+    return ReplaceAll(replacements, N);
+}
+
 // One byte operand of an instruction, for tables of byte patches.
 struct BytePatch {
     uint32_t instruction;