chore: remove internal docs and old release binaries from tracking

- docs/ untracked: internal dev docs (reports, sessions, plans) stay local
- dist/: keep only latest .deb (1.3.1) and .exe (1.1.0); remove 4 old builds
- .gitignore: ignore /docs/ and all dist binaries except the two latest

.gitignore

@@ -45,11 +45,17 @@ app.*.map.json
 /android/app/release
 
 # Distribution binaries — release assets, not tracked in git
+# (only the latest build of each type stays tracked for direct download)
 *.deb
 *.tar.gz
 *.exe
+!dist/imajviewer_1.3.1_amd64.deb
+!dist/imajviewer_setup_1.1.0.exe
 deb/usr/lib/imajviewer/
 release/
 
 # Local backup snapshots (see soul.md §5)
-docs/.bak/
+docs/.bak/
+
+# Internal dev docs stay local, not in the public repo
+/docs/