docs(readme): document contribution process

Amolith created

Adds a new section to the README detailing the collaboration workflow
using pr.pico.sh. This aims to simplify contributions by outlining
the patch request process clearly, removing barriers for new
contributors.

Change summary

README.md | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)

Detailed changes

README.md 🔗

@@ -90,6 +90,35 @@ The plugin will:
 - `repomix` command available in PATH
 - LLM CLI tool installed
 
+## Collaboration
+
+Patch requests are in [amolith/llm-projects] on [pr.pico.sh]. You don't need a
+new account to contribute, you don't need to fork this repo, you don't need to
+fiddle with `git send-email`, you don't need to faff with your email client to
+get `git request-pull` working...
+
+You just need:
+
+- Git
+- SSH
+- An SSH key
+
+```sh
+# Clone this repo, make your changes, and commit them
+# Create a new patch request with
+git format-patch origin/main --stdout | ssh pr.pico.sh pr create amolith/llm-projects
+# After potential feedback, submit a revision to an existing patch request with
+git format-patch origin/main --stdout | ssh pr.pico.sh pr add {prID}
+# List patch requests
+ssh pr.pico.sh pr list amolith/llm-projects
+```
+
+See "How do Patch Requests work?" on [pr.pico.sh]'s home page for a more
+complete example workflow.
+
+[amolith/llm-projects]: https://pr.pico.sh/r/amolith/llm-projects
+[pr.pico.sh]: https://pr.pico.sh
+
 ## License
 
 Apache-2.0