[CTX-1235] fix: route flat CR/LF key literals through Enter role

lua/composer/init.lua

@@ -770,13 +770,24 @@ end
 -- `key:Name` label; field-level modifier encodings stay parked with the
 -- input-pointer contract owner, so a flat label never matches a modified
 -- role (the explicit session commands stay the exact path). Returns the
--- chord, the string "literal" for produced text (the caller inserts it), or
--- nil for unmapped labels.
+-- chord, the string "literal" for produced text (the caller inserts it,
+-- except CR/LF below), or nil for unmapped labels.
 local function flat_key_shape(text)
   if type(text) ~= "string" or text == "" then
     return nil
   end
   if string.sub(text, 1, 4) ~= "key:" then
+    -- Headed Return arrives here, not as a label: both host capture entries
+    -- forward the produced `key.text` verbatim, and Return produces "\r"
+    -- (xkb/winit convention, the same byte the VT encoder emits for Enter).
+    -- A key-event CR/LF can only come from the Enter key itself (typing and
+    -- paste arrive as text/paste events, never key literals), so route it
+    -- through the bare Enter role for parity with the mock-chord and label
+    -- paths; otherwise custom enter-submits can never fire headed
+    -- (composer#21) and defaults silently bank a CR instead of a newline.
+    if text == "\r" or text == "\n" then
+      return { key = "enter", ctrl = false, alt = false, shift = false, super = false }
+    end
     return "literal"
   end
   local name = string.lower(string.sub(text, 5))

tests/scene-pump.test.ts

@@ -90,6 +90,41 @@ describe("production flat poll shape feeds the buffer", () => {
     expect(run.host.submittedFrames).toEqual([]);
   });
 
+  test("flat CR/LF literals route through the Enter role (composer#21)", async () => {
+    const run = await scenePump({ environment: { VISUAL: "nvim" } });
+    dispatch(run, OPEN_COMMAND);
+    injectFlat(run, { type: "key", text: "x" });
+    await pump(run);
+    expect(await bufferText(run)).toBe("x");
+    // Headed Return arrives as produced text "\r", not as a key:Enter
+    // label: under defaults it must newline exactly like the label path.
+    injectFlat(run, { type: "key", text: "\r" });
+    await pump(run);
+    expect(await bufferText(run)).toBe("x\n");
+    injectFlat(run, { type: "key", text: "\n" });
+    await pump(run);
+    expect(await bufferText(run)).toBe("x\n\n");
+    expect(await isOpen(run)).toBe(true);
+    expect(run.host.submittedFrames).toEqual([]);
+  });
+
+  test("flat CR literal submits under custom enter-submits (composer#21)", async () => {
+    const run = await scenePump({
+      environment: { VISUAL: "nvim" },
+      settings: { submit: "enter", newline: "shift+enter" },
+    });
+    dispatch(run, OPEN_COMMAND);
+    injectFlat(run, { type: "text", text: "CUSTOMSUB42" });
+    await pump(run);
+    injectFlat(run, { type: "key", text: "\r" });
+    await pump(run);
+    expect(await lastCode(run)).toBe("SUBMITTED");
+    expect(await isOpen(run)).toBe(false);
+    expect(await bufferText(run)).toBe("");
+    expect(run.host.submittedFrames).toHaveLength(1);
+    expect(run.host.submittedFrames[0]).toEqual(expectedFrame("CUSTOMSUB42"));
+  });
+
   test("flat key literals insert; key:Enter newlines; other labels swallow", async () => {
     const run = await scenePump({ environment: { VISUAL: "nvim" } });
     dispatch(run, OPEN_COMMAND);