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.

DataStore_Talents/DataStore_Talents.lua

@@ -234,7 +234,9 @@ local function _GetReferenceTable()
 end
 
 local function	_GetClassReference(class)
-	assert(type(class) == "string")
+	-- CoA: custom classes (MONK, BARBARIAN, …) have no vanilla reference table; return nil
+	-- instead of asserting/crashing so callers can degrade gracefully.
+	if type(class) ~= "string" then return end
 	return addon.ref.global[class]
 end
 
@@ -251,27 +253,28 @@ local function _IsClassKnown(class)
 	class = class or ""	-- if by any chance nil is passed, trap it to make sure the function does not fail, but returns nil anyway
 	
 	local ref = _GetClassReference(class)
-	if ref.Order then		-- if the Order field is not nil, we have data for this class
+	if ref and ref.Order then		-- CoA: ref is nil for custom classes; was an unguarded index crash
 		return true
 	end
 end
 
 local function _ImportClassReference(class, data)
-	assert(type(class) == "string")
-	assert(type(data) == "table")
-	
+	-- CoA: data arrives over Comm/AccountSharing; a peer with no reference for a custom
+	-- class can send nil, which used to crash the import. Skip silently instead.
+	if type(class) ~= "string" or type(data) ~= "table" then return end
+
 	addon.ref.global[class] = data
 end
 
 local function _GetClassTrees(class)
-	assert(type(class) == "string")
-	
+	-- CoA: ref is nil for custom classes; guard so the `for tree in DS:GetClassTrees()`
+	-- loops in Talents.lua get an empty iterator instead of an index-nil crash.
 	local ref = _GetClassReference(class)
-	local order = ref.Order
+	local order = ref and ref.Order
 	if order then
 		return order:gmatch("([^,]+)")
 	end
-	-- to do, add a return value that does not require validity testing by the caller
+	return function() return nil end		-- empty iterator so callers can loop safely
 end
 
 local function _GetTreeInfo(class, tree)
@@ -284,8 +287,7 @@ end
 
 local function _GetTreeNameByID(class, id)
 	-- returns the name of tree "id" for a given class
-	assert(type(class) == "string")
-	
+	-- CoA: _GetClassTrees now yields an empty iterator for custom classes, so no assert needed
 	local index = 1
 	for name in _GetClassTrees(class) do
 		if index == id then