test(runtime): lock reconciler, measure, flex, overflow, build-output (Ink parity) (#116)

Final round-2 test-only batch (behaviors already at parity with Ink reconciler.tsx,
measure-text.tsx, flex-*.tsx, overflow.tsx, build-output.ts):
- build-output: every package.json export target resolves on disk (runtime/cli/testing)
  + the .d.mts declaration sibling for the typed libraries (runtime/testing, not cli).
- reconciler: keyed insert-between [a,c]→[a,b,c]; replace a colored <Text> child with a
  plain string; setElementText A→B + the text-context guard; marginLeft removal reset.
- measure: empty <Text> contributes height 0 in a column; non-zero left (marginLeft=5 →
  5,1); measureTextNatural trailing/only-newline heights.
- flex: alignSelf='auto' == default + alignSelf removal resets to AUTO; the two
  space-around known-yoga-bug cases converted from test.skip to test.fails (they assert
  the DESIRED output and flip to a real failure if yoga ever fixes the bug); the documented
  flexDirection/flexWrap removal-reset divergence (was comment-only) now has a visual lock.
- overflow: out-of-bounds writes produce Ink's exact clipped frame (sparse past-width cell,
  filtered hole) — tightened from toBeDefined().
- components: inline + top-level non-empty fragment in <Text>; the previously-skipped
  ST-terminated OSC-8 hyperlink hard-wrap now passes ('abcde\nfghij') — un-skipped as a lock.

Codex-reviewed GENUINE.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/runtime-tests/integration/components/text.test.tsx

@@ -186,6 +186,66 @@ test("remeasure text when text nodes are changed", async () => {
   expect(lastFrame()).toBe("abcx");
 });
 
+// Ink reconciler.tsx:328-344 / components.tsx:715-731 ("replace child node with
+// text"): an outer <Text> whose only child is a colored <Text> is replaced across
+// a rerender by a plain string. The frame must flip from the colored "test" to a
+// bare "x" — the nested styled child node is fully torn down and the text-leaf
+// takes its place.
+test("replace a colored <Text> child with a plain string across a rerender", async () => {
+  const replace = shallowRef(false);
+  const { lastFrame } = await render(
+    defineComponent(() => () => (
+      <Text>{replace.value ? "x" : <Text color="green">test</Text>}</Text>
+    )),
+    { columns: 100 },
+  );
+  // Before: the nested green child is the only content → chalk.green("test").
+  expect(lastFrame()).toBe(chalk.green("test"));
+
+  replace.value = true;
+  await nextTick();
+  // After: the styled child is gone, replaced by a plain text-leaf → "x".
+  expect(lastFrame()).toBe("x");
+});
+
+// Locks the node-ops setElementText host op + remeasure: flipping <Text>A</Text>
+// to <Text>B</Text> goes through Vue's setElementText fast path (a single static
+// text child), which clears the leaf, inserts the new one, and dirties the text
+// measure owner so yoga remeasures. The frame must update A -> B.
+test("setElementText path updates A to B and remeasures", async () => {
+  const flip = shallowRef(false);
+  const { lastFrame } = await render(
+    defineComponent(() => () => <Text>{flip.value ? "B" : "A"}</Text>),
+    { columns: 100 },
+  );
+  expect(lastFrame()).toBe("A");
+
+  flip.value = true;
+  await nextTick();
+  expect(lastFrame()).toBe("B");
+});
+
+// The text-context guard fires only for NON-EMPTY raw text directly inside a
+// <Box>. Vue materializes the empty branch of `cond ? 'oops' : ''` as an empty
+// text-leaf (a fragment anchor), which node-ops insert() deliberately skips — so
+// the empty case renders "" without throwing, while the non-empty "oops" throws.
+test("<Box>{cond ? 'oops' : ''}</Box> throws for the non-empty branch only", async () => {
+  // `cond` drives the ternary at runtime (a literal true/false here is flagged as
+  // a constant condition by the linter; shallowRef keeps the exact two-branch shape).
+  const oopsCond = shallowRef(true);
+  const oops = defineComponent(() => () => <Box>{oopsCond.value ? "oops" : ""}</Box>);
+  await expect(render(oops)).rejects.toThrow(
+    /^Text string "oops" must be rendered inside <Text> component$/,
+  );
+
+  // The empty branch is a skipped fragment anchor — no text reaches the Box, so
+  // it renders an empty frame without tripping the guard.
+  const emptyCond = shallowRef(false);
+  const empty = defineComponent(() => () => <Box>{emptyCond.value ? "oops" : ""}</Box>);
+  const { lastFrame } = await render(empty, { columns: 100 });
+  expect(lastFrame()).toBe("");
+});
+
 test("text with content 'constructor' wraps correctly", async () => {
   const { lastFrame } = await render(
     defineComponent(() => () => <Text>constructor</Text>),
@@ -617,6 +677,35 @@ test("number", async () => {
   expect(lastFrame()).toBe("1");
 });
 
+// Ink components.tsx:80-88,363-372: a fragment nested inline inside <Text> is
+// flattened into the surrounding text run, so "Hello " + <>World</> squashes to
+// "Hello World" (the fragment contributes no layout of its own).
+test("inline fragment inside <Text> flattens into the text run", async () => {
+  const { lastFrame } = await render(
+    defineComponent(() => () => (
+      <Text>
+        Hello <>World</>
+      </Text>
+    )),
+    { columns: 100 },
+  );
+  expect(lastFrame()).toBe("Hello World");
+});
+
+// A top-level fragment wrapping a single <Text> renders as that text — the
+// fragment is transparent at the root, matching Ink's root-fragment handling.
+test("top-level fragment wrapping a <Text> renders the text", async () => {
+  const { lastFrame } = await render(
+    defineComponent(() => () => (
+      <>
+        <Text>Hello World</Text>
+      </>
+    )),
+    { columns: 100 },
+  );
+  expect(lastFrame()).toBe("Hello World");
+});
+
 test("do not wrap text with BEL-terminated OSC hyperlinks", async () => {
   const hyperlink = "\x1b]8;;https://example.com\x07Click here\x1b]8;;\x07";
   const output = renderToString(
@@ -739,8 +828,11 @@ test("hard-wrap text containing an inline erase-line (\\x1b[2K) sequence across
   expect(output).toBe(`${line1}\n${line2}`);
 });
 
-// Feature gap: ST-terminated OSC sequences not handled correctly in wrap-ansi path
-test.skip("hard-wrap single-word ST-terminated OSC hyperlink", async () => {
+// ST-terminated (ESC\) OSC-8 hyperlink, single long word, hard-wrapped at width 5.
+// The wrap protection covers both OSC terminators (BEL and ST), so the word breaks
+// at the cell boundary exactly like its BEL-terminated sibling above: "abcde\nfghij".
+// Verified against Ink v7.0.4 (un-skipped — vue produces Ink's identical output).
+test("hard-wrap single-word ST-terminated OSC hyperlink", async () => {
   const hyperlink = "\x1b]8;;https://example.com\x1b\\abcdefghij\x1b]8;;\x1b\\";
   const output = renderToString(
     defineComponent(() => () => (