Add per-character spellbook collector

New Collectors/Spellbook.lua walks GetNumSpellTabs() and emits one entry
per tab with name, texture, offset, numSpells, and a spells[] array of
{ slot, name, rank, spellID, icon }.

3.3.5/Ascension API differences are handled defensively: name comes
from GetSpellBookItemInfo or vanilla GetSpellName; spellID is parsed
out of GetSpellLink (3.3.5 doesn't return it from GetSpellBookItemInfo);
icon falls back to GetSpellTexture if GetSpellInfo doesn't have it yet.

Wiring:
  - CoaExporter.toc: load Collectors/Spellbook.lua after Talents
  - Core.lua: AssembleExport() includes spellbook for all + spellbook
  - Core.lua: HandleExport() accepts /coae export spellbook
  - Core.lua: debug output shows tab + spell counts
  - UI/ExportFrame.lua: "Spellbook" button in the Character section

CoaExporter/Core.lua

@@ -47,6 +47,9 @@ function AE:AssembleExport(which)
     if wantAll or which == "talents" then
         if AE.CollectTalents then out.talents = SafeCall(AE.CollectTalents) or {} end
     end
+    if wantAll or which == "spellbook" then
+        if AE.CollectSpellbook then out.spellbook = SafeCall(AE.CollectSpellbook) or {} end
+    end
     if wantAll or which == "gear" then
         if AE.CollectGear then out.gear = SafeCall(AE.CollectGear) or {} end
     end
@@ -331,7 +334,7 @@ end
 local HELP = [[
 CoaExporter commands:
 
-/coae export all|talents|gear|enchants
+/coae export all|talents|spellbook|gear|enchants
 /coae export mdgear|mdenchants|md (full wiki)
 /coae catalog all|skills|talents
 /coae catalog dispels [class]|passives [class]|status
@@ -349,7 +352,7 @@ local function HandleExport(rest)
         AE:ShowExport(AE:GenerateMarkdownEnchants(), "CoaExporter - Markdown Enchants (Ctrl+C)")
     elseif rest == "md" or rest == "mdfull" or rest == "wiki" then
         AE:ShowExport(AE:GenerateMarkdownFull(), "CoaExporter - Wiki Markdown (Ctrl+C)")
-    elseif rest == "all" or rest == "talents" or rest == "gear" or rest == "enchants" then
+    elseif rest == "all" or rest == "talents" or rest == "spellbook" or rest == "gear" or rest == "enchants" then
         AE:Export(rest)
     else
         DEFAULT_CHAT_FRAME:AddMessage("CoaExporter: unknown export target '" .. tostring(rest) .. "'")
@@ -442,10 +445,10 @@ local function HandleDebug()
     add(string.format("- AddOn: %s", tostring(ADDON_NAME)))
     add(string.format("- UI: %s", type(_G.CoaExporter_ShowExportFrame) == "function" and "yes" or "no"))
     add(string.format("- JSON: %s", type(_G.CoaExporter_Json_Encode) == "function" and "yes" or "no"))
-    add(string.format("- Loaded: talents=%s gear=%s enchants=%s scrolls=%s probe=%s catCommon=%s catSkills=%s catTalents=%s",
-        tostring(AE._loadedTalents or false), tostring(AE._loadedGear or false),
-        tostring(AE._loadedEnchants or false), tostring(AE._loadedMysticScrolls or false),
-        tostring(AE._loadedMysticScrollProbe or false),
+    add(string.format("- Loaded: talents=%s spellbook=%s gear=%s enchants=%s scrolls=%s probe=%s catCommon=%s catSkills=%s catTalents=%s",
+        tostring(AE._loadedTalents or false), tostring(AE._loadedSpellbook or false),
+        tostring(AE._loadedGear or false), tostring(AE._loadedEnchants or false),
+        tostring(AE._loadedMysticScrolls or false), tostring(AE._loadedMysticScrollProbe or false),
         tostring(AE._loadedCatalogCommon or false), tostring(AE._loadedCatalogSkills or false),
         tostring(AE._loadedCatalogTalents or false)))
 
@@ -456,6 +459,13 @@ local function HandleDebug()
     else
         add("Talents: MISSING")
     end
+    if type(AE.CollectSpellbook) == "function" then
+        local sb = SafeCall(AE.CollectSpellbook) or {}
+        add(string.format("Spellbook: OK, tabs=%d, spells=%d",
+            #(sb.tabs or {}), sb.totalSpells or 0))
+    else
+        add("Spellbook: MISSING")
+    end
     if type(AE.CollectGear) == "function" then
         local g = SafeCall(AE.CollectGear) or {}
         add(string.format("Gear: OK, slots=%d", #(g.slots or {})))