literate: add org sources for orphan test files, update README

- Create org/integration-tests.org (15 blocks, per-test prose)
- Add Markdown tests section to org/markdown-renderer.org (11 test blocks)
- Delete deprecated src/components/input-tests.lisp stub
- Update README.org: tree diagram, literate programming section,
  development commands, remove stale test counts

All 13 test suites pass at 100%. Zero .lisp files without org origin.

README.org

@@ -309,7 +309,7 @@ Result is cached in ~*detected-backend*~.
 * Development
 
 #+BEGIN_SRC bash
-# Run all tests (483 checks, 13 suites)
+# Run all tests
 sbcl --script run-all-tests.lisp
 
 # Run interactive demo
@@ -317,13 +317,18 @@ sbcl --script demo.lisp
 
 # Tangle org files (regenerate .lisp from .org sources)
 python3 ~/.hermes/skills/software-development/org-babel-tangle/scripts/tangle.py org/*.org
+
+# Verify syntax of all tangled files
+for f in src/**/*.lisp tests/*.lisp; do
+  sbcl --eval "(with-open-file (s \"$f\") (loop for e = (read s nil s) until (eq e s)))" \
+       --eval "(format t \"~a: OK~%\" \"$f\")" --quit 2>/dev/null
+done
 #+END_SRC
 
-Literate programming: ~.org~ files in ~org/~ are the source of truth for
-the input system, scrollbox/tabbar, dialog, mouse, select, slot,
-framebuffer, and markdown modules. The backend (~modern.lisp~,
-~simple.lisp~) and basic components (~box.lisp~, ~text.lisp~, ~render.lisp~,
-~theme.lisp~, ~dirty.lisp~) are written directly.
+Literate programming: every ~.lisp~ file in ~src/~ and ~tests/~ is a generated
+artifact from an ~.org~ file in ~org/~. The org files are the source of truth.
+Each function has its own code block with prose explaining the design reasoning.
+Delete every ~.lisp~ file and they can all be regenerated by tangling the org files.
 
 Project structure:
 
@@ -332,46 +337,51 @@ cl-tty/
 ├── cl-tty.asd              # ASDF system definition
 ├── demo.lisp               # Interactive demo
 ├── run-all-tests.lisp      # Test runner
-├── src/backend/                    # Backend protocol + implementations
-│   ├── package.lisp
-│   ├── classes.lisp                # Generic definitions
-│   ├── simple.lisp                 # ASCII fallback backend
-│   ├── modern.lisp                 # Truecolor escape backend
-│   └── detection.lisp              # Auto-detect backend from env
-├── src/layout/                     # Flexbox layout engine
-│   └── layout.lisp
 ├── src/
-│   ├── rendering/          # Framebuffer backend + diff + flush
+│   ├── backend/            # Backend protocol + implementations
+│   │   ├── package.lisp, classes.lisp
+│   │   ├── simple.lisp, modern.lisp
+│   │   └── detection.lisp
+│   ├── layout/             # Flexbox layout engine
+│   │   └── layout.lisp
+│   ├── rendering/          # Framebuffer diffing pipeline
 │   │   └── framebuffer.lisp
-│   └── components/         # Widgets
-│       ├── box.lisp, text.lisp, render.lisp, theme.lisp
-│       ├── dirty.lisp, input-package.lisp, input.lisp
+│   └── components/         # Widget library
+│       ├── package.lisp, dirty.lisp, render.lisp, theme.lisp
+│       ├── box.lisp, text.lisp
+│       ├── input-package.lisp, input.lisp
 │       ├── text-input.lisp, textarea.lisp, keybindings.lisp
-│       ├── scrollbox.lisp, tabbar.lisp, container-package.lisp
-│       ├── select.lisp, select-package.lisp
-│       ├── markdown.lisp, markdown-package.lisp
-│       ├── dialog.lisp, dialog-package.lisp
-│       ├── mouse.lisp, mouse-package.lisp
-│       └── slot.lisp, slot-package.lisp
-├── tests/                  # Test files
-├── org/                    # Literate source files
+│       ├── container-package.lisp, scrollbox.lisp, tabbar.lisp
+│       ├── select-package.lisp, select.lisp
+│       ├── markdown-package.lisp, markdown.lisp
+│       ├── dialog-package.lisp, dialog.lisp
+│       ├── mouse-package.lisp, mouse.lisp
+│       └── slot-package.lisp, slot.lisp
+├── tests/                  # FiveAM test files
+│   ├── input-tests.lisp, scrollbox-tabbar-tests.lisp
+│   ├── select-tests.lisp, markdown-tests.lisp
+│   ├── dialog-tests.lisp, mouse-tests.lisp, slot-tests.lisp
+│   ├── framebuffer-tests.lisp, integration-tests.lisp
+│   ├── box-tests.lisp, dirty-tests.lisp, render-tests.lisp
+│   └── theme-tests.lisp
+├── org/                    # Literate source (all .lisp files come from here)
+│   ├── package.org, dirty.org, render.org, theme.org
+│   ├── box-renderable.org
 │   ├── text-input.org
-│   ├── scrollbox.org
-│   ├── tabbar.org
-│   ├── container-package.org
+│   ├── scrollbox.org, tabbar.org, container-package.org
+│   ├── select.org
+│   ├── markdown-renderer.org
 │   ├── dialog.org
 │   ├── mouse.org
-│   ├── select.org
 │   ├── slot.org
+│   ├── backend-protocol.org, modern-backend.org, detection.org
+│   ├── layout-engine.org
 │   ├── framebuffer.org
-│   ├── markdown-renderer.org
-│   ├── detection.org
-│   ├── modern-backend.org
-│   ├── box-renderable.org
-│   └── layout-engine.org
-└── docs/
-    ├── ROADMAP.org         # Versioned roadmap
-    └── ARCHITECTURE.org    # Design docs
+│   └── integration-tests.org
+├── docs/
+│   ├── ROADMAP.org
+│   └── ARCHITECTURE.org
+└── demo/                   # Demo assets (optional)
 #+END_EXAMPLE
 
 * License