fix(quotes): wire no-quote toggle into process-page UI gates

The server-side PDF route was already no-quote-aware — when
`quote.is_no_quote === true` it bypasses the pricing gate
(`pdf/route.ts:156, 238, 240`) and the PDF component renders "Not
quoted" cells + "—" totals (`quote-document.tsx:239, 242, 276/280/285`).
But the client side was ignoring the flag, so flipping the toggle
looked like a no-op. Five one-file fixes to close the gap:

1. `itemsReady` now short-circuits to true when no-quote is on.
   Before: `itemsReady = items.length > 0 && missingSupplier === 0 &&
   missingPricing === 0;` (always evaluated pricing). After: prepend
   `isNoQuote ||` so the Generate Quote button enables regardless of
   cost/selling prices. (Bug A)

2. `applyPricing` markup>0 guard now bypassed when no-quote is on.
   Before: toast "Markup must be greater than 0" + refuse save when
   markup ≤ 0 — blocked the operator from saving a 0/0/0 row. After:
   `if (!isNoQuote && ...)` so the operator can save the row. (Bug B)

3. `handlePricingChange` auto-derive now skipped when no-quote is on.
   The cost↔selling recompute on every keystroke (`value * (1 + markup
   / 100)` and inverse) was firing even when no-quote was set, which
   is what produced the "I set 0/0/1% markup and it shows 1 cent"
   artefact. Three branches (markup/cost/selling) now short-circuit
   to pass-through under no-quote. (Bug C)

4. Helper text under the Generate Quote PDF button now explains
   "No-quote letter — prices ignored on PDF (renders 'Not quoted'
   cells)" when the toggle is on, instead of the misleading
   "Price every item + assign a supplier before generating".

5. Second helper line under the toggle's label explaining the full
   UI flow when on: "the pricing form stays editable but isn't
   required, and the PDF renders 'Not quoted' cells with no totals."

Operator workflow now: flip toggle ON → enter description on a row
at 0/0/0 → save → click Generate Quote → PDF renders decline letter
with "Not quoted" cells and no totals. No PB migration needed
(`is_no_quote` boolean column already present per `pb-exports/pb_schema-2.json:2178`).

Build: clean. Typecheck: 0 errors. No tests added (manual flow; no
existing test exercises this toggle path).

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

src/app/(app)/quotes/[id]/process/page.tsx

@@ -690,15 +690,12 @@ export default function QuoteProcessPage({ params }: { params: Promise<{ id: str
 
   const applyPricing = () => {
     if (!pricingModal) return;
-    // Markup must be present and strictly positive. A zero markup
-    // (cost = selling) is a giveaway, not a quote — the office
-    // can't run a business on it. A negative markup means we're
-    // selling below cost, which the supplier PO and accounting
-    // both reject. Surface a clear error and refuse to save; the
-    // operator can either type a positive value in the Markup
-    // field or adjust the cost/selling pair so the recomputed
-    // markup lands above zero.
-    if (!Number.isFinite(pricingForm.markup) || pricingForm.markup <= 0) {
+    // Markup must be present and strictly positive — UNLESS this is a
+    // no-quote (decline-letter). In no-quote mode the PDF route
+    // renders "Not quoted" cells and "—" totals, so a row at 0/0/0
+    // is exactly the target. Forcing markup > 0 would block the
+    // operator from saving the row, which is the bug Bug B fixes.
+    if (!isNoQuote && (!Number.isFinite(pricingForm.markup) || pricingForm.markup <= 0)) {
       toast.error("Markup must be greater than 0 — adjust the cost or selling price so the markup is positive.");
       return;
     }
@@ -728,9 +725,14 @@ export default function QuoteProcessPage({ params }: { params: Promise<{ id: str
   ) => {
     setPricingForm((prev) => {
       // Markup is always editable; it doesn't get locked. Recompute
-      // whichever side isn't locked.
+      // whichever side isn't locked — UNLESS this is a no-quote
+      // (decline-letter). In no-quote mode the prices don't matter
+      // for the PDF render, so we let the operator type whatever
+      // they want without the form auto-recomputing the other side
+      // (the Bug C fix).
       if (field === "markup") {
         const next = { ...prev, markup: value };
+        if (isNoQuote) return next;
         if (pricingLock === "cost") {
           next.selling_price = round2(prev.cost_price * (1 + value / 100));
         } else {
@@ -742,21 +744,25 @@ export default function QuoteProcessPage({ params }: { params: Promise<{ id: str
       // Typing into cost — if selling is locked, switch the lock to cost.
       if (field === "cost_price") {
         if (pricingLock === "selling") setPricingLock("cost");
-        return {
-          ...prev,
-          cost_price: value,
-          selling_price: round2(value * (1 + prev.markup / 100)),
-        };
+        return isNoQuote
+          ? { ...prev, cost_price: value }
+          : {
+              ...prev,
+              cost_price: value,
+              selling_price: round2(value * (1 + prev.markup / 100)),
+            };
       }
 
       // Typing into selling — if cost is locked, switch the lock to selling.
       // selling: field === "selling_price"
       if (pricingLock === "cost") setPricingLock("selling");
-      return {
-        ...prev,
-        selling_price: value,
-        cost_price: prev.markup > -100 ? round2(value / (1 + prev.markup / 100)) : 0,
-      };
+      return isNoQuote
+        ? { ...prev, selling_price: value }
+        : {
+            ...prev,
+            selling_price: value,
+            cost_price: prev.markup > -100 ? round2(value / (1 + prev.markup / 100)) : 0,
+          };
     });
   };
 
@@ -864,7 +870,12 @@ export default function QuoteProcessPage({ params }: { params: Promise<{ id: str
   const missingPricing = items.filter(
     (i) => !(i.cost_price && i.selling_price),
   ).length;
-  const itemsReady = items.length > 0 && missingSupplier === 0 && missingPricing === 0;
+  // No-quote (decline-letter) mode bypasses the pricing gate entirely
+  // — the PDF route renders every line with "Not quoted" cells and
+  // "—" totals, so a row with cost=0 / selling=0 / markup=0 is
+  // exactly what we want. See Bug A in the no-quote findings.
+  const itemsReady =
+    isNoQuote || (items.length > 0 && missingSupplier === 0 && missingPricing === 0);
 
   return (
     <div className="space-y-4 max-w-7xl mx-auto">
@@ -969,6 +980,11 @@ export default function QuoteProcessPage({ params }: { params: Promise<{ id: str
                 <p className="text-xs text-muted-foreground">
                   Send this as an official decline. Prices will be ignored.
                 </p>
+                <p className="text-xs text-muted-foreground">
+                  When on: the pricing form stays editable but isn&apos;t
+                  required, and the PDF renders &quot;Not quoted&quot;
+                  cells with no totals.
+                </p>
               </div>
               <Switch
                 id="is_no_quote"
@@ -1636,9 +1652,11 @@ export default function QuoteProcessPage({ params }: { params: Promise<{ id: str
             <div>
               <p className="text-sm font-medium">Generate Quote PDF</p>
               <p className="text-xs text-muted-foreground">
-                {itemsReady
-                  ? "Select a letterhead template"
-                  : `Price every item + assign a supplier before generating (${missingPricing} unpriced, ${missingSupplier} missing supplier)`}
+                {isNoQuote
+                  ? "No-quote letter — prices ignored on PDF (renders 'Not quoted' cells)"
+                  : itemsReady
+                    ? "Select a letterhead template"
+                    : `Price every item + assign a supplier before generating (${missingPricing} unpriced, ${missingSupplier} missing supplier)`}
               </p>
             </div>
             <div className="flex gap-2">