fix(tui): inherit markdown foreground colors

Pass the active transcript foreground into retained Markdown renderables so unhighlighted fenced code remains visible on light terminal backgrounds. Update existing renderables during theme changes and cover the history hydration path that exposed the regression.

tui/src/app.test.ts

@@ -2102,6 +2102,42 @@ describe("NanobotTui layout", () => {
     ))).toBeTrue()
   })
 
+  test("renders fenced plain text from light-theme history", async () => {
+    setup = await createRenderer({ width: 100, height: 30, screenMode: "alternate-screen" })
+    const app = NanobotTui.mount(
+      setup.renderer,
+      { ...options, theme: "light" },
+      client(),
+      new MockTreeSitterClient({ autoResolveTimeout: 0 }),
+    )
+    const response = [
+      "Commit types:",
+      "",
+      "```text",
+      "feat:",
+      "fix:",
+      "perf:",
+      "docs:",
+      "test:",
+      "refactor:",
+      "chore:",
+      "```",
+      "",
+      "Include the reason in the body.",
+    ].join("\n")
+    const transcript = (app as unknown as { transcript: Transcript }).transcript
+
+    transcript.history([{ role: "assistant", content: response }])
+    await setup.flush()
+
+    const code = setup.captureSpans().lines
+      .flatMap((line) => line.spans)
+      .find((span) => span.text.includes("feat:"))
+
+    expect(setup.captureCharFrame()).toContain("feat:")
+    expect(code?.fg.toInts().slice(0, 3)).toEqual([24, 24, 27])
+  })
+
   test("renders assistant LaTeX as Unicode text without changing code", async () => {
     setup = await createRenderer({ width: 96, height: 24, screenMode: "alternate-screen" })
     const app = mount(setup)
@@ -2152,7 +2188,7 @@ describe("NanobotTui layout", () => {
         syntaxStyle: { getStyle(name: string): { fg?: { toInts(): number[] } } | undefined } | null
       }
       transcript: {
-        markdown: Set<{ syntaxStyle: object }>
+        markdown: Set<{ fg?: { toInts(): number[] }; syntaxStyle: object }>
         frames: Set<{ borderColor: { toInts(): number[] } }>
         userRows: Set<{ backgroundColor: { intent: string; toInts(): number[] } }>
         userMessages: Set<{ renderable: TextRenderable }>
@@ -2186,6 +2222,7 @@ describe("NanobotTui layout", () => {
     expect(internals.composer.textColor.toInts().slice(0, 3)).toEqual([24, 24, 27])
     expect(sessionFrame?.borderColor.toInts().slice(0, 3)).toEqual([212, 212, 216])
     expect(userRow?.backgroundColor.toInts().slice(0, 3)).toEqual([240, 240, 240])
+    expect(markdown?.fg?.toInts().slice(0, 3)).toEqual([24, 24, 27])
     expect(markdown?.syntaxStyle).not.toBe(darkSyntax)
     expect(internals.composer.syntaxStyle).not.toBe(darkComposerSyntax)
     expect(internals.composer.syntaxStyle?.getStyle("image.placeholder")?.fg?.toInts().slice(0, 3))

tui/src/transcript.ts

@@ -183,7 +183,10 @@ export class Transcript {
         message.displayContent,
       )
     }
-    for (const renderable of this.markdown) renderable.syntaxStyle = theme.syntax
+    for (const renderable of this.markdown) {
+      renderable.fg = theme.text
+      renderable.syntaxStyle = theme.syntax
+    }
     for (const frame of this.frames) frame.borderColor = theme.border
     for (const row of this.userRows) {
       row.backgroundColor = theme.userBackground
@@ -664,6 +667,7 @@ export class Transcript {
       minWidth: 0,
       flexGrow: 1,
       flexShrink: 1,
+      fg: this.theme.text,
       syntaxStyle: this.theme.syntax,
       streaming,
       internalBlockMode: "top-level",