docs(amiga): complete AmigaOS 3.1/3.2 developer reference — 172 files across 17 sections

Comprehensive technical documentation covering:
- Hardware: OCS/ECS/AGA custom chip registers, Copper & Blitter deep dives
- Boot sequence: cold boot through startup-sequence
- Binary format: HUNK executable spec, relocation, debug info
- Linking & ABI: .fd files, LVO tables, register calling conventions
- Exec kernel: tasks, interrupts, memory, signals, semaphores
- AmigaDOS: file I/O, FFS/OFS layout, CLI/Shell scripting
- Graphics: planar bitmaps, Copper programming, HAM/EHB modes
- Intuition: screens, windows, IDCMP, BOOPSI
- Devices: trackdisk, SCSI, serial, timer, audio, keyboard
- Libraries: utility, expansion, IFFParse, locale, ARexx
- Networking: bsdsocket API, SANA-II, TCP/IP stack comparison
- Toolchain: GCC, vasm/vlink, SAS/C, NDK, debugging
- Reverse engineering: IDA/Ghidra setup, compiler fingerprints, case studies
- CPU & MMU: 68040/060 emulation libs, PMMU, cache management
- Driver development: SANA-II, Picasso96/RTG, AHI audio

All files include breadcrumb navigation. No local paths or proprietary content.

09_intuition/menus.md

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+[← Home](../README.md) · [Intuition](README.md)
+
+# Menus — MenuStrip Construction
+
+## Overview
+
+Intuition menus are structured as: `Menu` → `MenuItem` → `SubItem`. Menus are attached to windows and appear when the user presses the right mouse button.
+
+---
+
+## GadTools Menu Creation (OS 2.0+)
+
+```c
+struct NewMenu nm[] = {
+    { NM_TITLE,  "Project",   NULL, 0, 0, NULL },
+    {  NM_ITEM,  "New",       "N",  0, 0, NULL },
+    {  NM_ITEM,  "Open...",   "O",  0, 0, NULL },
+    {  NM_ITEM,  NM_BARLABEL, NULL, 0, 0, NULL },  /* separator */
+    {  NM_ITEM,  "Quit",      "Q",  0, 0, NULL },
+    { NM_TITLE,  "Edit",      NULL, 0, 0, NULL },
+    {  NM_ITEM,  "Cut",       "X",  0, 0, NULL },
+    {  NM_ITEM,  "Copy",      "C",  0, 0, NULL },
+    {  NM_ITEM,  "Paste",     "V",  0, 0, NULL },
+    { NM_END,    NULL,        NULL, 0, 0, NULL }
+};
+
+struct Menu *menu = CreateMenus(nm, TAG_DONE);
+LayoutMenus(menu, vi, TAG_DONE);
+SetMenuStrip(win, menu);
+
+/* In event loop on IDCMP_MENUPICK: */
+UWORD code = imsg->Code;
+while (code != MENUNULL) {
+    struct MenuItem *item = ItemAddress(menu, code);
+    UWORD menuNum  = MENUNUM(code);
+    UWORD itemNum  = ITEMNUM(code);
+    UWORD subNum   = SUBNUM(code);
+    /* process selection */
+    code = item->NextSelect;
+}
+
+/* Cleanup: */
+ClearMenuStrip(win);
+FreeMenus(menu);
+```
+
+---
+
+## Menu Selection Macros
+
+```c
+#define MENUNUM(code)   ((code) & 0x1F)        /* menu number (0–31) */
+#define ITEMNUM(code)   (((code) >> 5) & 0x3F)  /* item number (0–63) */
+#define SUBNUM(code)    (((code) >> 11) & 0x1F)  /* subitem number */
+#define FULLMENUNUM(m,i,s) ((m)|((i)<<5)|((s)<<11))
+#define MENUNULL        0xFFFF                   /* no selection */
+```
+
+---
+
+## References
+
+- NDK39: `libraries/gadtools.h`, `intuition/intuition.h`
+- ADCD 2.1: `CreateMenus`, `LayoutMenus`, `SetMenuStrip`