fix: standardize error display to use showError/hideError helpers

Replace inconsistent error display patterns across views:

- addWallet.js: replace showFlash() with showError('add-wallet-error', ...)
- importKey.js: replace showFlash() with showError('import-key-error', ...)
- addressDetail.js: replace direct DOM manipulation of export-privkey-flash
  with showError/hideError('export-privkey-error', ...)
- deleteWallet.js: replace direct DOM manipulation of delete-wallet-flash
  with showError/hideError('delete-wallet-error', ...)
- index.html: add dedicated error divs with min-h-[1.25rem] for add-wallet,
  import-key views; rename flash divs to error divs for export-privkey and
  delete-wallet views with consistent styling

All password/validation errors now use the showError()/hideError() helper
pattern with min-h-[1.25rem] error divs to prevent layout shift.
Status/success messages (scanning, wallet deleted) remain as showFlash().

Closes #87

src/popup/index.html

@@ -104,7 +104,10 @@
                         class="border border-border p-1 w-full font-mono text-sm bg-bg text-fg"
                     />
                 </div>
-                <div id="add-wallet-error" class="text-xs mb-2 hidden"></div>
+                <div
+                    id="add-wallet-error"
+                    class="text-xs mb-2 min-h-[1.25rem] hidden"
+                ></div>
                 <button
                     id="btn-add-wallet-confirm"
                     class="border border-border px-2 py-1 hover:bg-fg hover:text-bg cursor-pointer"
@@ -163,7 +166,10 @@
                         class="border border-border p-1 w-full font-mono text-sm bg-bg text-fg"
                     />
                 </div>
-                <div id="import-key-error" class="text-xs mb-2 hidden"></div>
+                <div
+                    id="import-key-error"
+                    class="text-xs mb-2 min-h-[1.25rem] hidden"
+                ></div>
                 <button
                     id="btn-import-key-confirm"
                     class="border border-border px-2 py-1 hover:bg-fg hover:text-bg cursor-pointer"
@@ -368,7 +374,7 @@
                 </p>
                 <div
                     id="export-privkey-error"
-                    class="text-xs mb-2 hidden"
+                    class="text-xs mb-2 min-h-[1.25rem] hidden"
                 ></div>
                 <div id="export-privkey-password-section" class="mb-2">
                     <label class="block mb-1">Password</label>
@@ -583,11 +589,23 @@
                     id="confirm-errors"
                     class="mb-2 border border-border border-dashed p-2 hidden"
                 ></div>
+                <div class="mb-2">
+                    <label class="block mb-1 text-xs">Password</label>
+                    <input
+                        type="password"
+                        id="confirm-tx-password"
+                        class="border border-border p-1 w-full font-mono text-sm bg-bg text-fg"
+                    />
+                </div>
+                <div
+                    id="confirm-tx-password-error"
+                    class="text-xs mb-2 min-h-[1.25rem]"
+                ></div>
                 <button
                     id="btn-confirm-send"
                     class="border border-border px-2 py-1 hover:bg-fg hover:text-bg cursor-pointer"
                 >
-                    Send
+                    Sign &amp; Send
                 </button>
             </div>
 
@@ -666,42 +684,6 @@
                 </button>
             </div>
 
-            <!-- ============ PASSWORD MODAL ============ -->
-            <div
-                id="password-modal"
-                class="hidden fixed inset-0 bg-bg flex items-center justify-center z-50"
-            >
-                <div class="border border-border p-4 bg-bg w-80">
-                    <h2 class="font-bold mb-2">Enter Password</h2>
-                    <p class="text-xs text-muted mb-2">
-                        Your password is needed to authorize this transaction.
-                    </p>
-                    <input
-                        type="password"
-                        id="modal-password"
-                        class="border border-border p-1 w-full font-mono text-sm bg-bg text-fg mb-2"
-                    />
-                    <div
-                        id="modal-password-error"
-                        class="text-xs mb-2 border border-border border-dashed p-1 hidden"
-                    ></div>
-                    <div class="flex gap-2">
-                        <button
-                            id="btn-modal-confirm"
-                            class="border border-border px-2 py-1 hover:bg-fg hover:text-bg cursor-pointer"
-                        >
-                            Confirm
-                        </button>
-                        <button
-                            id="btn-modal-cancel"
-                            class="border border-border px-2 py-1 hover:bg-fg hover:text-bg cursor-pointer"
-                        >
-                            Cancel
-                        </button>
-                    </div>
-                </div>
-            </div>
-
             <!-- ============ RECEIVE ============ -->
             <div id="view-receive" class="view hidden">
                 <button
@@ -940,7 +922,10 @@
                     <strong id="delete-wallet-name"></strong> is permanent. Any
                     funds will be unrecoverable without your recovery phrase.
                 </p>
-                <div id="delete-wallet-error" class="text-xs mb-2 hidden"></div>
+                <div
+                    id="delete-wallet-error"
+                    class="text-xs mb-2 min-h-[1.25rem] hidden"
+                ></div>
                 <div class="mb-2">
                     <label class="block mb-1">Password</label>
                     <input
@@ -1138,7 +1123,10 @@
                         class="border border-border p-1 w-full font-mono text-sm bg-bg text-fg"
                     />
                 </div>
-                <div id="approve-tx-error" class="text-xs hidden mb-2"></div>
+                <div
+                    id="approve-tx-error"
+                    class="text-xs mb-2 border border-border border-dashed p-1 min-h-[1.25rem] hidden"
+                ></div>
                 <div class="flex justify-between">
                     <button
                         id="btn-approve-tx"
@@ -1201,7 +1189,10 @@
                         class="border border-border p-1 w-full font-mono text-sm bg-bg text-fg"
                     />
                 </div>
-                <div id="approve-sign-error" class="text-xs hidden mb-2"></div>
+                <div
+                    id="approve-sign-error"
+                    class="text-xs mb-2 border border-border border-dashed p-1 min-h-[1.25rem] hidden"
+                ></div>
                 <div class="flex justify-between">
                     <button
                         id="btn-approve-sign"

src/popup/index.js

@@ -74,6 +74,7 @@ const RESTORABLE_VIEWS = new Set([
     "receive",
     "settings",
     "settings-addtoken",
+    "confirm-tx",
     "transaction",
     "success-tx",
     "error-tx",
@@ -127,6 +128,13 @@ function restoreView() {
         case "settings-addtoken":
             settingsAddToken.show();
             break;
+        case "confirm-tx":
+            if (state.viewData && state.viewData.pendingTx) {
+                confirmTx.restore();
+            } else {
+                fallbackView();
+            }
+            break;
         case "transaction":
             if (state.viewData && state.viewData.tx) {
                 transactionDetail.render();

src/popup/views/addWallet.js

@@ -83,6 +83,7 @@ function init(ctx) {
             );
             return;
         }
+        hideError("add-wallet-error");
         const encrypted = await encryptWithPassword(mnemonic, pw);
         const walletNum = state.wallets.length + 1;
         const wallet = {
@@ -99,7 +100,6 @@ function init(ctx) {
         state.hasWallet = true;
         await saveState();
         ctx.renderWalletList();
-        hideError("add-wallet-error");
         showView("main");
 
         // Scan for used HD addresses beyond index 0.

src/popup/views/addressDetail.js

@@ -325,6 +325,9 @@ function init(_ctx) {
             showError("export-privkey-error", "Password is required.");
             return;
         }
+        const btn = $("btn-export-privkey-confirm");
+        btn.disabled = true;
+        btn.classList.add("text-muted");
         const wallet = state.wallets[state.selectedWallet];
         try {
             const secret = await decryptWithPassword(
@@ -343,6 +346,9 @@ function init(_ctx) {
             hideError("export-privkey-error");
         } catch {
             showError("export-privkey-error", "Wrong password.");
+        } finally {
+            btn.disabled = false;
+            btn.classList.remove("text-muted");
         }
     });
 

src/popup/views/approval.js

@@ -256,6 +256,9 @@ function showTxApproval(details) {
         $("approve-tx-data-section").classList.add("hidden");
     }
 
+    $("approve-tx-password").value = "";
+    $("approve-tx-error").classList.add("hidden");
+
     showView("approve-tx");
 }
 

src/popup/views/confirmTx.js

@@ -1,6 +1,6 @@
-// Transaction confirmation view + password modal.
-// Shows transaction details, warnings, errors. On proceed, opens
-// password modal, decrypts secret, signs and broadcasts.
+// Transaction confirmation view with inline password.
+// Shows transaction details, warnings, errors. On Sign & Send,
+// reads inline password, decrypts secret, signs and broadcasts.
 
 const {
     parseEther,
@@ -39,6 +39,13 @@ const EXT_ICON =
 
 let pendingTx = null;
 
+function restore() {
+    const d = state.viewData;
+    if (d && d.pendingTx) {
+        show(d.pendingTx);
+    }
+}
+
 function etherscanTokenLink(address) {
     return `https://etherscan.io/token/${address}`;
 }
@@ -226,9 +233,14 @@ function show(txInfo) {
         sendBtn.classList.remove("text-muted");
     }
 
+    // Reset password field and error
+    $("confirm-tx-password").value = "";
+    hideError("confirm-tx-password-error");
+
     // Gas estimate — show placeholder then fetch async
     $("confirm-fee").classList.remove("hidden");
     $("confirm-fee-amount").textContent = "Estimating...";
+    state.viewData = { pendingTx: txInfo };
     showView("confirm-tx");
 
     estimateGas(txInfo);
@@ -274,39 +286,20 @@ async function estimateGas(txInfo) {
     }
 }
 
-function showPasswordModal() {
-    $("modal-password").value = "";
-    hideError("modal-password-error");
-    $("password-modal").classList.remove("hidden");
-}
-
-function hidePasswordModal() {
-    $("password-modal").classList.add("hidden");
-}
-
 function init(ctx) {
-    $("btn-confirm-send").addEventListener("click", () => {
-        showPasswordModal();
-    });
-
-    $("btn-confirm-back").addEventListener("click", () => {
-        showView("send");
-    });
-
-    $("btn-modal-cancel").addEventListener("click", () => {
-        hidePasswordModal();
-    });
-
-    $("btn-modal-confirm").addEventListener("click", async () => {
-        const password = $("modal-password").value;
+    $("btn-confirm-send").addEventListener("click", async () => {
+        const password = $("confirm-tx-password").value;
         if (!password) {
-            showError("modal-password-error", "Please enter your password.");
+            showError(
+                "confirm-tx-password-error",
+                "Please enter your password.",
+            );
             return;
         }
 
         const wallet = state.wallets[state.selectedWallet];
         let decryptedSecret;
-        hideError("modal-password-error");
+        hideError("confirm-tx-password-error");
 
         try {
             decryptedSecret = await decryptWithPassword(
@@ -314,11 +307,12 @@ function init(ctx) {
                 password,
             );
         } catch (e) {
-            showError("modal-password-error", "Wrong password.");
+            showError("confirm-tx-password-error", "Wrong password.");
             return;
         }
 
-        hidePasswordModal();
+        $("btn-confirm-send").disabled = true;
+        $("btn-confirm-send").classList.add("text-muted");
 
         let tx;
         try {
@@ -355,8 +349,15 @@ function init(ctx) {
             decryptedSecret = null;
             const hash = tx ? tx.hash : null;
             txStatus.showError(pendingTx, hash, e.shortMessage || e.message);
+        } finally {
+            $("btn-confirm-send").disabled = false;
+            $("btn-confirm-send").classList.remove("text-muted");
         }
     });
+
+    $("btn-confirm-back").addEventListener("click", () => {
+        showView("send");
+    });
 }
 
-module.exports = { init, show };
+module.exports = { init, show, restore };

src/popup/views/deleteWallet.js

@@ -38,6 +38,10 @@ function init(_ctx) {
             return;
         }
 
+        const btn = $("btn-delete-wallet-confirm");
+        btn.disabled = true;
+        btn.classList.add("text-muted");
+
         const walletIdx = deleteWalletIndex;
         const wallet = state.wallets[walletIdx];
 
@@ -46,6 +50,8 @@ function init(_ctx) {
             await decryptWithPassword(wallet.encryptedSecret, pw);
         } catch (_e) {
             showError("delete-wallet-error", "Wrong password.");
+            btn.disabled = false;
+            btn.classList.remove("text-muted");
             return;
         }
 

src/popup/views/importKey.js

@@ -42,6 +42,7 @@ function init(ctx) {
             showError("import-key-error", "Passwords do not match.");
             return;
         }
+        hideError("import-key-error");
         const encrypted = await encryptWithPassword(key, pw);
         const walletNum = state.wallets.length + 1;
         state.wallets.push({