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

tests/input-utils.test.ts

@@ -83,4 +83,4 @@ describe("Input Utils", () => {
       expect(cleanInput("")).toBe("");
     });
   });
-});
+});