chore(#1): Add PyPI publish step and Gitea registry install instructions

- Add publish step to .woodpecker.yml that builds wheel/sdist and uploads
  to git.mosaicstack.dev PyPI registry via twine (gated on all quality
  checks, only on main/develop/tags)
- Add link-package step to associate PyPI package with the repository
- Update README and integration guide with Gitea registry install
  instructions (pip --index-url, uv --index-url, pyproject.toml config)
- Version check prevents re-publishing existing versions

Refs #1

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

README.md

@@ -6,10 +6,31 @@ Python client SDK for [Mosaic Stack Telemetry](https://github.com/mosaicstack/te
 
 ## Installation
 
+Install from the Mosaic Stack package registry:
+
 ```bash
-pip install mosaicstack-telemetry
-# or
-uv add mosaicstack-telemetry
+pip install mosaicstack-telemetry --index-url https://git.mosaicstack.dev/api/packages/mosaic/pypi/simple/
+```
+
+Or with [uv](https://docs.astral.sh/uv/):
+
+```bash
+uv add mosaicstack-telemetry --index-url https://git.mosaicstack.dev/api/packages/mosaic/pypi/simple/
+```
+
+To avoid passing `--index-url` every time, add the registry to your project's `pyproject.toml`:
+
+```toml
+[[tool.uv.index]]
+name = "mosaic"
+url = "https://git.mosaicstack.dev/api/packages/mosaic/pypi/simple/"
+```
+
+Or to `pip.conf` / `~/.config/pip/pip.conf`:
+
+```ini
+[global]
+extra-index-url = https://git.mosaicstack.dev/api/packages/mosaic/pypi/simple/
 ```
 
 Runtime dependencies: `httpx` and `pydantic`.