ci: add typechecking, fail fast in CI, and patch typechecking errors (#63)

src/cli/components/AdvancedDiffRenderer.tsx

@@ -281,7 +281,9 @@ export function AdvancedDiffRenderer(
     let newNo = h.newStart;
     let lastRemovalNo: number | null = null;
     for (let i = 0; i < h.lines.length; i++) {
-      const raw = h.lines[i].raw || "";
+      const line = h.lines[i];
+      if (!line) continue;
+      const raw = line.raw || "";
       const ch = raw.charAt(0);
       const body = raw.slice(1);
       // Skip meta lines (e.g., "\ No newline at end of file"): do not display, do not advance counters,
@@ -291,7 +293,9 @@ export function AdvancedDiffRenderer(
       // Helper to find next non-meta '+' index
       const findNextPlus = (start: number): string | undefined => {
         for (let j = start + 1; j < h.lines.length; j++) {
-          const r = h.lines[j].raw || "";
+          const nextLine = h.lines[j];
+          if (!nextLine) continue;
+          const r = nextLine.raw || "";
           if (r.charAt(0) === "\\") continue; // skip meta
           if (r.startsWith("+")) return r.slice(1);
           break; // stop at first non-meta non-plus
@@ -301,7 +305,9 @@ export function AdvancedDiffRenderer(
       // Helper to find previous non-meta '-' index
       const findPrevMinus = (start: number): string | undefined => {
         for (let k = start - 1; k >= 0; k--) {
-          const r = h.lines[k].raw || "";
+          const prevLine = h.lines[k];
+          if (!prevLine) continue;
+          const r = prevLine.raw || "";
           if (r.charAt(0) === "\\") continue; // skip meta
           if (r.startsWith("-")) return r.slice(1);
           break; // stop at first non-meta non-minus

src/cli/components/MarkdownDisplay.tsx

@@ -77,7 +77,7 @@ export const MarkdownDisplay: React.FC<MarkdownDisplayProps> = ({
 
     // Check for headers
     const headerMatch = line.match(headerRegex);
-    if (headerMatch) {
+    if (headerMatch?.[1] && headerMatch[2] !== undefined) {
       const level = headerMatch[1].length;
       const content = headerMatch[2];
 
@@ -119,7 +119,12 @@ export const MarkdownDisplay: React.FC<MarkdownDisplayProps> = ({
 
     // Check for list items
     const listMatch = line.match(listItemRegex);
-    if (listMatch) {
+    if (
+      listMatch &&
+      listMatch[1] !== undefined &&
+      listMatch[2] &&
+      listMatch[3] !== undefined
+    ) {
       const indent = listMatch[1].length;
       const marker = listMatch[2];
       const content = listMatch[3];
@@ -146,7 +151,7 @@ export const MarkdownDisplay: React.FC<MarkdownDisplayProps> = ({
 
     // Check for blockquotes
     const blockquoteMatch = line.match(blockquoteRegex);
-    if (blockquoteMatch) {
+    if (blockquoteMatch && blockquoteMatch[1] !== undefined) {
       contentBlocks.push(
         <Box key={key} paddingLeft={2}>
           <Text dimColor>│ </Text>

src/cli/components/PasteAwareTextInput.tsx

@@ -60,6 +60,8 @@ export function PasteAwareTextInput({
     onSubmit?: (value: string) => void;
     placeholder?: string;
     focus?: boolean;
+    externalCursorOffset?: number;
+    onCursorOffsetChange?: (n: number) => void;
   }>;
 
   // Sync external value changes (treat incoming value as DISPLAY value)