Add versioning convention

README.md

@@ -0,0 +1,50 @@
+# jhaas
+
+Home lab / personal projects. This repo has no code — Forgejo renders its
+`README.md` on the profile page, so it's used to hold conventions that
+apply across every repo below, instead of duplicating them in each one.
+
+## Versioning: `YY.MAJOR.MINOR-BUILD`
+
+All projects version releases (git tags, changelog entries, artifact
+filenames) as:
+
+```
+YY.MAJOR.MINOR-BUILD
+```
+
+Example: **`26.0.0-1`**
+
+| Field   | Meaning                                             | Effect when bumped          |
+|---------|------------------------------------------------------|------------------------------|
+| `YY`    | Two-digit calendar year of the release                | —                             |
+| `MAJOR` | Breaking / incompatible change                         | resets `MINOR` → 0, `BUILD` → 1 |
+| `MINOR` | New feature, non-breaking addition                      | resets `BUILD` → 1            |
+| `BUILD` | Anything else on the same `YY.MAJOR.MINOR` (fix, rebuild, tweak) | +1                    |
+
+`YY` simply tracks the calendar year the release happened in — it does not
+by itself force a `MAJOR`/`MINOR`/`BUILD` reset. A project can go from
+`25.2.1-4` straight to `26.2.1-5` if nothing breaking or new landed around
+New Year's.
+
+### Example progression
+
+```
+26.0.0-1   first release of the year, MAJOR 0 / MINOR 0
+26.0.0-2   bugfix rebuild, same MAJOR.MINOR
+26.1.0-1   new feature added -> MINOR bumped, BUILD reset
+26.1.0-2   another small fix
+27.0.0-1   breaking redesign, new year -> MAJOR bumped, MINOR/BUILD reset
+```
+
+### Git tags
+
+Tag releases as `vYY.MAJOR.MINOR-BUILD`, e.g. `v26.0.0-1`.
+
+### Where this shows up
+
+- Git tags on the release commit
+- `CHANGELOG.md` (if the project has one)
+- Optionally, a small version string in a project's `docs/index.html`
+  footer (see [projects-hub](https://git.joha.mywire.org/jhaas/projects-hub)
+  for the hub convention those pages follow)