fix: a send the confirmation screen refuses moves nothing on it (closes #583)

Sign & Send wrote its refusals, a network changed since review and a gas limit or fee over its bound, into the errors box above the password field. That box reserves one empty line, so a refusal grew it and pushed the password field and Sign & Send down.

Each refusal now has its own box with its sentence fixed in index.html, holding its space from the first paint and only made visible, as #558 did for the balance messages. One sentence is true of all three bounds and quotes no number; the full reason is logged. A Chrome test raises the stub node's fee only at signing and checks nothing moved; a unit test refuses a gas limit over its bound into the same box.

Model: opus-5-5

tests/confirmTxNetworkSwitch.test.js

@@ -440,12 +440,8 @@ describe.each([
             expect(mockNode.broadcast).toEqual([]);
             expect(txStatus.showWait).not.toHaveBeenCalled();
             expect(txStatus.showError).not.toHaveBeenCalled();
-            expect(el("confirm-errors").style.visibility).toBe("visible");
-            expect(el("confirm-errors").innerHTML).toContain(
-                "The active network changed after this transaction was" +
-                    " reviewed, so it was not sent. Please go back and review" +
-                    " it again.",
-            );
+            expect(shown("confirm-network-changed-error")).toBe(true);
+            expect(shown("confirm-fee-bound-error")).toBe(false);
         });
     },
 );
@@ -497,10 +493,7 @@ describe.each([
             expect(mockNode.broadcast).toEqual([]);
             expect(txStatus.showWait).not.toHaveBeenCalled();
             expect(txStatus.showError).not.toHaveBeenCalled();
-            expect(el("confirm-errors").innerHTML).toContain(
-                "The active network changed after this transaction was" +
-                    " reviewed, so it was not sent.",
-            );
+            expect(shown("confirm-network-changed-error")).toBe(true);
         });
 
         test("is sent on that network, as described, once it is chosen in Settings again and Back pressed", async () => {
@@ -579,10 +572,7 @@ describe.each([
 
             expect(signTransaction).not.toHaveBeenCalled();
             expect(mockNode.broadcast).toEqual([]);
-            expect(errors()).toContain(
-                "The active network changed after this transaction was" +
-                    " reviewed, so it was not sent.",
-            );
+            expect(shown("confirm-network-changed-error")).toBe(true);
         });
 
         const tokenSend = {
@@ -629,10 +619,7 @@ describe.each([
 
             expect(signTransaction).not.toHaveBeenCalled();
             expect(mockNode.broadcast).toEqual([]);
-            expect(errors()).toContain(
-                "The active network changed after this transaction was" +
-                    " reviewed, so it was not sent.",
-            );
+            expect(shown("confirm-network-changed-error")).toBe(true);
         });
 
         test("with a fee quoted by a node with no type-2 pricing, shows the fee in that network's native currency and price", async () => {