coa.17: comprehensive partial-data hardening + DataStore_Characters login scan + Skills strip cap

- Hardening sweep across DataStore_* (softened crash-asserts in Talents/Containers/Quests
  to graceful nil) + Altoholic frames (guarded remaining getter results).
- DataStore_Characters: scan on login (was ghost-gated -> name/level/class never populated;
  the core 'no character data' cause).
- Skills tab: cap inline professions at 6 (+N) so the strip stops overflowing into Cooking.

Altoholic/Frames/GuildProfessions.lua

@@ -25,9 +25,9 @@ local PrimaryLevelSort = {	-- sort functions for the mains
 			end
 		end,
 	["level"] = function(a, b)
-			local levelA = select(4, DataStore:GetGuildMemberInfo(a.name))
-			local levelB = select(4, DataStore:GetGuildMemberInfo(b.name))
-			
+			local levelA = select(4, DataStore:GetGuildMemberInfo(a.name)) or 0		-- CoA: nil level on partial guild data crashed table.sort
+			local levelB = select(4, DataStore:GetGuildMemberInfo(b.name)) or 0
+
 			if viewSortOrder then
 				return levelA < levelB
 			else
@@ -76,9 +76,9 @@ local SecondaryLevelSort = {-- sort functions for the alts
 			end
 		end,
 	["level"] = function(a, b)
-			local levelA = select(4, DataStore:GetGuildMemberInfo(a))
-			local levelB = select(4, DataStore:GetGuildMemberInfo(b))
-			
+			local levelA = select(4, DataStore:GetGuildMemberInfo(a)) or 0		-- CoA: nil level on partial guild data crashed table.sort
+			local levelB = select(4, DataStore:GetGuildMemberInfo(b)) or 0
+
 			if viewSortOrder then
 				return levelA < levelB
 			else
@@ -199,6 +199,7 @@ local function DisplayProfessionLink(frameName, member, index)
 		local icon = addon:TextureToFontstring(addon:GetSpellIcon(tonumber(spellID)), 18, 18) .. " "
 		if link then
 			local curRank, maxRank = DataStore:GetProfessionInfo(link)
+			curRank, maxRank = curRank or 0, maxRank or 0		-- CoA: GetProfessionInfo returns nil if the link doesn't match the trade pattern
 			local ts = addon.TradeSkills
 			text:SetText(icon .. ts:GetColor(curRank) .. curRank .. "/" .. maxRank)
 		else
@@ -350,7 +351,8 @@ function ns:OnEnter(self)
 	if not spellID or not link then return end
 
 	local curRank, maxRank = DataStore:GetProfessionInfo(link)
-	
+	curRank, maxRank = curRank or 0, maxRank or 0		-- CoA: nil ranks when link doesn't match trade pattern; guard concat below
+
 	AltoTooltip:ClearLines();
 	AltoTooltip:SetOwner(self, "ANCHOR_RIGHT");