Initial commit: Chatter — assistive-writing app for reMarkable Paper Pro Move

Direct-framebuffer ink pipeline (stock-quality strokes), finger-wipe erase,
growable scrolling canvas with color-ghost cleanup, bidirectional toggle with a
persistent 4-finger return launcher, instant button feedback. Includes prebuilt
aarch64 binaries (dist/), build/deploy/install scripts, a user guide, and a
complete technical reference.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tools/setbufshim.cpp

@@ -0,0 +1,35 @@
+// Feasibility check: can we intercept EPFramebuffer::setBuffers to capture the
+// framebuffer's backing QImages? setBuffers is called from the epaper platform
+// plugin (libepaper) into libqsgepaper — a cross-DSO call, so unlike swapBuffers
+// it should be interposable via LD_PRELOAD. If this fires and reports real image
+// dimensions + a pixel pointer, the direct-framebuffer ink pipeline is viable.
+//
+// ABI: std::tuple<QImage,QImage> is non-trivially-copyable, so it's passed by
+// reference (a pointer); QImage* is a pointer. So three pointer args after this.
+
+#include <QImage>
+#include <tuple>
+#include <dlfcn.h>
+#include <cstdio>
+
+extern "C" void _ZN13EPFramebuffer10setBuffersESt5tupleIJ6QImageS1_EEPS1_(
+    void *self, void *tuplePtr, void *imgPtr)
+{
+    static void (*real)(void *, void *, void *) = nullptr;
+    if (!real)
+        real = (void (*)(void *, void *, void *))dlsym(
+            RTLD_NEXT, "_ZN13EPFramebuffer10setBuffersESt5tupleIJ6QImageS1_EEPS1_");
+
+    auto *t = reinterpret_cast<std::tuple<QImage, QImage> *>(tuplePtr);
+    QImage *c = reinterpret_cast<QImage *>(imgPtr);
+    const QImage &a = std::get<0>(*t);
+    const QImage &b = std::get<1>(*t);
+    fprintf(stderr,
+            "SETBUFFERS self=%p | A=%dx%d fmt=%d bytesPerLine=%d cbits=%p | "
+            "B=%dx%d fmt=%d | C=%p %dx%d\n",
+            self, a.width(), a.height(), int(a.format()), a.bytesPerLine(),
+            (const void *)a.constBits(), b.width(), b.height(), int(b.format()),
+            (void *)c, c ? c->width() : -1, c ? c->height() : -1);
+
+    if (real) real(self, tuplePtr, imgPtr);
+}