README: pure markdown, and a logo sized for a README

The <img> tag existed only to set a width, and the <div align=center> only to
centre things -- neither of which markdown can express. Sizing the image file
itself removes the reason for both: logo-trans.png was a 1024x1024 1.7MB
master being scaled down in the browser on every page load, and is now 400x400
and 219KB. Nothing else uses it (the splash reads logo.png and logo.ans), and
the original is in git history if it is ever wanted back.

So the README is now plain markdown end to end: ![](), no divs, and the footer
is a link instead of a centred <sub>. Left-aligned rather than centred, which
is what markdown does.

2 files changed, 4 insertions, 8 deletions

diff --git a/README.md b/README.md
index af0669a..e551a8e 100644
--- a/README.md
+++ b/README.md
@@ -1,13 +1,9 @@
-<div align="center">
-
-<img src="logo-trans.png" alt="ida-tui" width="420">
+![ida-tui](logo-trans.png)
 
 **IDA Pro in a terminal.** Listing, decompiler, graph — keyboard-first, mouse-capable.
 
 `disasm` · `pseudocode` · `cfg` · `hex` · `strings` · `structs` · `traces` · `rpc`
 
-</div>
-
 ---
 
 ```
@@ -175,6 +171,6 @@ flake, and the four ways a test here wastes minutes.
 - A GUI user editing the same database won't invalidate our caches — Code Mode
   has no change feed yet (see `docs/CODEMODE_UPSTREAM.md`).
 
-<div align="center">
-<sub><a href="https://sl0p.foo">sl0p.foo</a></sub>
-</div>
+—
+
+[sl0p.foo](https://sl0p.foo)
diff --git a/logo-trans.png b/logo-trans.png
index 65d576b..1dd3387 100644
--- a/logo-trans.png
+++ b/logo-trans.png