Improve agent autonomy and diff view readability

Agent behavior improvements:
  - Add project context detection (tsconfig.json, pom.xml, etc.)
  - Enforce validation after changes (tsc --noEmit, mvn compile, etc.)
  - Run tests automatically - never ask "do you want me to run tests"
  - Complete full loop: create → type-check → test → confirm
  - Add command detection for direct execution (run tree, run ls)

  Diff view improvements:
  - Use darker backgrounds for added/removed lines
  - Add diffLineBgAdded, diffLineBgRemoved, diffLineText theme colors
  - Improve text visibility with white text on dark backgrounds
  - Update both React/Ink and SolidJS diff components

  Streaming fixes:
  - Fix tool call argument accumulation using OpenAI index field
  - Fix streaming content display after tool calls
  - Add consecutive error tracking to prevent token waste

  Other changes:
  - ESC to abort operations, Ctrl+C to exit
  - Fix model selection when provider changes in cascade mode
  - Add debug logging for troubleshooting
  - Move tests to root tests/ folder
  - Fix banner test GRADIENT_COLORS reference

src/ui/banner.test.ts

@@ -0,0 +1,105 @@
+import { getBannerLines } from "./banner/lines";
+import { renderBanner, renderBannerWithSubtitle } from "./banner/render";
+import { printBanner, printWelcome } from "./banner/print";
+import { getInlineLogo } from "./banner/logo";
+import { BANNER_STYLE_MAP, BANNER_LINES, GRADIENT_COLORS } from "@constants/banner";
+import { Style } from "@ui/styles";
+
+describe("Banner Utilities", () => {
+  describe("getBannerLines", () => {
+    it("should return default banner lines when no style is provided", () => {
+      const lines = getBannerLines();
+      expect(lines).toEqual(BANNER_LINES);
+    });
+
+    it("should return banner lines for a specific style", () => {
+      const style = "blocks";
+      const lines = getBannerLines(style);
+      expect(lines).toEqual(BANNER_STYLE_MAP[style]);
+    });
+
+    it("should return default banner lines for an unknown style", () => {
+      const lines = getBannerLines("unknown-style" as any);
+      expect(lines).toEqual(BANNER_LINES);
+    });
+  });
+
+  describe("renderBanner", () => {
+    it("should render banner with default style", () => {
+      const banner = renderBanner();
+      const expectedLines = BANNER_LINES.map((line, index) => {
+        const colorIndex = Math.min(index, GRADIENT_COLORS.length - 1);
+        const color = GRADIENT_COLORS[colorIndex];
+        return color + line + Style.RESET;
+      }).join("\n");
+
+      expect(banner).toBe(expectedLines);
+    });
+
+    it("should render banner with a specific style", () => {
+      const style = "blocks";
+      const banner = renderBanner(style);
+      const expectedLines = BANNER_STYLE_MAP[style].map((line, index) => {
+        const colorIndex = Math.min(index, GRADIENT_COLORS.length - 1);
+        const color = GRADIENT_COLORS[colorIndex];
+        return color + line + Style.RESET;
+      }).join("\n");
+
+      expect(banner).toBe(expectedLines);
+    });
+  });
+
+  describe("renderBannerWithSubtitle", () => {
+    it("should render banner with subtitle", () => {
+      const subtitle = "Welcome to CodeTyper!";
+      const style = "default";
+      const bannerWithSubtitle = renderBannerWithSubtitle(subtitle, style);
+      const banner = renderBanner(style);
+      const expectedSubtitle = Style.DIM + "  " + subtitle + Style.RESET;
+
+      expect(bannerWithSubtitle).toBe(banner + "\n" + expectedSubtitle);
+    });
+  });
+
+  describe("printBanner", () => {
+    it("should print the banner to the console", () => {
+      const consoleSpy = jest.spyOn(console, "log").mockImplementation(() => {});
+      const style = "default";
+
+      printBanner(style);
+
+      expect(consoleSpy).toHaveBeenCalledWith("\n" + renderBanner(style));
+      consoleSpy.mockRestore();
+    });
+  });
+
+  describe("printWelcome", () => {
+    it("should print the welcome message to the console", () => {
+      const consoleSpy = jest.spyOn(console, "log").mockImplementation(() => {});
+      const version = "1.0.0";
+      const provider = "OpenAI";
+      const model = "GPT-4";
+
+      printWelcome(version, provider, model);
+
+      expect(consoleSpy).toHaveBeenCalledWith("\n" + renderBanner("blocks"));
+      expect(consoleSpy).toHaveBeenCalledWith("");
+      expect(consoleSpy).toHaveBeenCalledWith(Style.DIM + "  AI Coding Assistant" + Style.RESET);
+      expect(consoleSpy).toHaveBeenCalledWith("");
+      expect(consoleSpy).toHaveBeenCalledWith(
+        Style.DIM + `  v${version} | ${provider} | ${model}` + Style.RESET
+      );
+      expect(consoleSpy).toHaveBeenCalledWith("");
+
+      consoleSpy.mockRestore();
+    });
+  });
+
+  describe("getInlineLogo", () => {
+    it("should return the inline logo with correct style", () => {
+      const logo = getInlineLogo();
+      const expectedLogo = Style.CYAN + Style.BOLD + "codetyper" + Style.RESET;
+      expect(logo).toBe(expectedLogo);
+    });
+  });
+});