Redesign Break Even Timeline as cost-vs-revenue lines

Replaces the single net-profit curve with two cumulative lines: a
straight revenue line from zero and a jagged cost line starting at
the upfront manufacturing spend, stepping up at each cycle's
logistics cost and creeping up from repairs. This reads more
directly than the old cumulative-profit area chart, whose unified
hover tooltip was also showing confusing duplicate zero-valued
entries from the shading traces — now fixed with clean, pre-formatted
hover text and hoverinfo="skip" on the shading layers.

Also fixes the Strategy view's "Cycle Cost" slider, which was wired
up but never actually read by the break-even/revenue math (a
hardcoded 150 NOK was used instead), and changes the default Cycle
Length from 12 to 8 months.

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

app.py

@@ -252,7 +252,7 @@ if "strategy_portfolio" not in st.session_state:
 if "strategy_reuse_cycles" not in st.session_state:
     st.session_state.strategy_reuse_cycles = 4
 if "strategy_cycle_length" not in st.session_state:
-    st.session_state.strategy_cycle_length = 12
+    st.session_state.strategy_cycle_length = 8
 if "strategy_customer_base" not in st.session_state:
     st.session_state.strategy_customer_base = 1000
 
@@ -523,7 +523,7 @@ if selected_view == "Strategy":
     # CALCULATIONS
     # ============================================================
     lease_term_months = st.session_state.strategy_cycle_length
-    logistics_per_cycle = 150  # NOK - pickup + delivery per cycle
+    logistics_per_cycle = st.session_state.logistics_cost_per_cycle  # NOK - pickup + delivery per cycle
     repair_per_cycle = 200  # NOK - average repair/refurb per cycle
 
     # Per-product economics
@@ -590,46 +590,93 @@ if selected_view == "Strategy":
     if monthly_lease == 0:
         st.warning("Set a lease price above 0 NOK to see the break-even timeline.")
     else:
-        # Scale chart length with reuse cycles (each cycle = 12 months)
+        # Scale chart length with reuse cycles (each cycle = lease_term_months long)
         chart_months = min(reuse_cycles * lease_term_months, len(breakeven_cumulative) - 1)
         be_months = list(range(chart_months + 1))
-        be_values = breakeven_cumulative[:chart_months + 1]
+
+        # Revenue builds steadily from zero. Cost starts at the upfront
+        # manufacturing spend, then climbs: a small continuous rise from repairs,
+        # plus a step at the start of every cycle when logistics are paid.
+        monthly_revenue_val = portfolio_size * monthly_lease
+        monthly_repair_val = portfolio_size * (repair_per_cycle / lease_term_months)
+        initial_investment = portfolio_size * s_mfg_cost
+
+        revenue_cum = [monthly_revenue_val * m for m in be_months]
+        cost_cum = [
+            initial_investment + monthly_repair_val * m
+            + portfolio_size * logistics_per_cycle * (m // lease_term_months)
+            for m in be_months
+        ]
+
+        be_lead = f'Cost starts at <b>{sfmt(initial_investment)} NOK</b> — the upfront manufacturing spend — and climbs in steps as logistics and repairs are paid. Revenue builds steadily from zero.'
+        if breakeven_month and breakeven_month <= chart_months:
+            lead_gap = revenue_cum[-1] - cost_cum[-1]
+            be_lead += f' Revenue overtakes cost in <b>month {breakeven_month}</b>, and the portfolio is <b>{sfmt(lead_gap)} NOK</b> ahead by month {chart_months}.'
+        else:
+            be_lead += f' Cost still leads revenue after {chart_months} months at these settings.'
+        st.markdown(f'<p style="color: {COLORS["text_muted"]}; font-size: 0.95rem; margin: 0 0 1rem 0;">{be_lead}</p>', unsafe_allow_html=True)
+
+        # Pre-formatted hover text (matches the rest of the app's number style,
+        # instead of Plotly's default SI-suffix auto-formatting)
+        rev_hover = [f"+{sfmt(v)} NOK" for v in revenue_cum]
+        cost_hover = [f"-{sfmt(v)} NOK" for v in cost_cum]
 
         fig_be = go.Figure()
 
-        # Split into loss (red) and profit (green) fill zones
-        loss_y = [v if v <= 0 else 0 for v in be_values]
-        profit_y = [v if v >= 0 else 0 for v in be_values]
+        # Shaded gap between the lines — red while cost leads, teal once revenue overtakes it.
+        # hoverinfo is skipped so these don't clutter the tooltip.
+        crossing = breakeven_month if (breakeven_month and breakeven_month <= chart_months) else chart_months
+        if crossing > 0:
+            fig_be.add_trace(go.Scatter(
+                x=be_months[:crossing + 1] + be_months[:crossing + 1][::-1],
+                y=cost_cum[:crossing + 1] + revenue_cum[:crossing + 1][::-1],
+                mode="none", fill="toself", fillcolor="rgba(160, 68, 74, 0.16)",
+                hoverinfo="skip", showlegend=False,
+            ))
+        if crossing < chart_months:
+            fig_be.add_trace(go.Scatter(
+                x=be_months[crossing:] + be_months[crossing:][::-1],
+                y=revenue_cum[crossing:] + cost_cum[crossing:][::-1],
+                mode="none", fill="toself", fillcolor="rgba(18, 75, 95, 0.12)",
+                hoverinfo="skip", showlegend=False,
+            ))
 
         fig_be.add_trace(go.Scatter(
-            x=be_months, y=loss_y, mode="none", name="Loss period",
-            fill="tozeroy", fillcolor="rgba(160, 68, 74, 0.15)",
-            showlegend=False,
-        ))
-        fig_be.add_trace(go.Scatter(
-            x=be_months, y=profit_y, mode="none", name="Profit zone",
-            fill="tozeroy", fillcolor="rgba(18, 75, 95, 0.15)",
-            showlegend=False,
+            x=be_months, y=revenue_cum, mode="lines", name="Cumulative revenue",
+            line=dict(color=COLORS["primary"], width=3),
+            customdata=rev_hover,
+            hovertemplate="Month %{x}<br>Revenue: <b>%{customdata}</b><extra></extra>",
         ))
         fig_be.add_trace(go.Scatter(
-            x=be_months, y=be_values, mode="lines", name="Cumulative Profit",
-            line=dict(color=COLORS["primary"], width=3),
+            x=be_months, y=cost_cum, mode="lines", name="Cumulative cost",
+            line=dict(color=COLORS["negative"], width=3),
+            customdata=cost_hover,
+            hovertemplate="Month %{x}<br>Cost: <b>%{customdata}</b><extra></extra>",
         ))
-        fig_be.add_hline(y=0, line_color=COLORS["border"], line_width=1)
 
         if breakeven_month and breakeven_month <= chart_months:
+            cross_y = revenue_cum[breakeven_month]
             fig_be.add_trace(go.Scatter(
-                x=[breakeven_month], y=[breakeven_cumulative[breakeven_month]],
-                mode="markers+text", name="Break-even",
-                marker=dict(size=14, color=COLORS["warning"], symbol="diamond"),
-                text=[f"Month {breakeven_month}"], textposition="top center",
+                x=[breakeven_month], y=[cross_y], mode="markers",
+                marker=dict(size=14, color=COLORS["warning"], symbol="diamond",
+                            line=dict(color="white", width=1.5)),
+                hoverinfo="skip", showlegend=False,
             ))
+            fig_be.add_annotation(
+                x=breakeven_month, y=cross_y,
+                text=f"<b>Break-even — month {breakeven_month}</b>",
+                showarrow=True, arrowhead=2, arrowcolor=COLORS["warning"], ax=0, ay=-45,
+                bgcolor="white", bordercolor=COLORS["warning"], borderwidth=1, borderpad=4,
+                font=dict(size=12, color=COLORS["text"]),
+            )
 
         fig_be.update_layout(
-            xaxis_title="Months", yaxis_title="Cumulative Profit (NOK)",
-            showlegend=False, yaxis=dict(separatethousands=True),
+            xaxis_title="Months", yaxis_title="Cumulative NOK",
+            showlegend=True, yaxis=dict(separatethousands=True),
+            margin=dict(t=30),
         )
         st.plotly_chart(fig_be, use_container_width=True)
+        st.caption(f"Cost steps up at the start of each {lease_term_months}-month cycle (logistics) and creeps up between cycles (repairs); revenue accrues steadily from the lease price.")
 
     st.markdown("---")