Sell advisor: flag the weakest combo piece on a full board

JCA.weakest_link() scores each owned joker's total synergy against the
rest of the board (same capped scoring the shop advice uses) and returns
the lowest scorer — only when the board is full (that's when a cut
decision exists), has 3+ jokers, and one joker actually stands out
(uniform boards return nil). The owned-joker tooltip gains a red
'Weakest combo piece - a sell candidate' verdict line, suppressed in
learning mode like the other verdicts. Config toggle: sell_advisor.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

main.lua

@@ -152,6 +152,28 @@ function JCA.is_recommended(card)
     return total >= JCA.config.threshold
 end
 
+-- Sell advisor: on a full board, the owned joker contributing the least
+-- total synergy to the rest is the natural cut when something better shows
+-- up. Returns nil when slots are free, the board is tiny, or every joker
+-- scores the same (nothing stands out to cut).
+function JCA.weakest_link()
+    if not (G.jokers and G.jokers.cards) then return nil end
+    local cards = G.jokers.cards
+    local limit = G.jokers.config and G.jokers.config.card_limit or #cards
+    if #cards < 3 or #cards < limit then return nil end
+    local worst, worst_total, best_total
+    for _, c in ipairs(cards) do
+        if c.config and c.config.center and c.config.center.set == 'Joker' then
+            local _, total = JCA.partners_for(c)
+            if not worst_total or total < worst_total then
+                worst, worst_total = c, total
+            end
+            if not best_total or total > best_total then best_total = total end
+        end
+    end
+    if worst and worst_total < best_total then return worst end
+end
+
 local function in_buy_area(card)
     return card.area and (card.area == G.shop_jokers or card.area == G.pack_cards)
 end
@@ -290,6 +312,12 @@ local function tooltip_rows(card)
     end
     local caution = in_buy_area(card) and JCA.cautions[key]
     if caution then text_row('Caution: ' .. caution, G.C.RED) end
+    -- Sell advisor verdict (owned jokers only; suppressed in learning mode
+    -- like the other verdicts).
+    if JCA.config.sell_advisor and not JCA.config.learning_mode
+        and card.area == G.jokers and JCA.weakest_link() == card then
+        text_row('Weakest combo piece - a sell candidate', G.C.RED)
+    end
     rows.name = 'Combo Advisor'
     return rows
 end
@@ -978,6 +1006,12 @@ if SMODS.current_mod then
                     ref_table = JCA.config, ref_value = 'partner_highlight',
                 },
             }},
+            {n = G.UIT.R, config = {align = 'cm', padding = 0.05}, nodes = {
+                create_toggle{
+                    label = 'Flag weakest joker when board is full',
+                    ref_table = JCA.config, ref_value = 'sell_advisor',
+                },
+            }},
             {n = G.UIT.R, config = {align = 'cm', padding = 0.05}, nodes = {
                 create_toggle{
                     label = 'Learning mode (no verdicts, just reasons)',