Add prebuilt binaries, remove GitHub releases link

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.gitignore

@@ -1,4 +1,3 @@
 /target
-/dist
 .claude
 CITRINE_SPEC.md

README.md

@@ -4,7 +4,7 @@ Minimalist, plaintext, project-based todo CLI. Creates `.citrine` files in your
 
 ## Install
 
-Download a binary from [releases](https://github.com/syntaxbullet/citrine/releases) or build from source:
+Prebuilt binaries are in the `dist/` directory, or build from source:
 
 ```bash
 cargo install --path .