wiki: add alternatives section with SearXNG, FreshRSS, and Gitea

Add three new articles to 03-opensource/alternatives/:
- SearXNG: private metasearch, Open WebUI integration
- FreshRSS: self-hosted RSS, mobile app sync, OPML portability
- Gitea: lightweight GitHub alternative, webhook pipeline

Article count: 33 → 36. Open source section: 6 → 9.

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

03-opensource/alternatives/gitea.md

@@ -0,0 +1,95 @@
+# Gitea — Self-Hosted Git
+
+## Problem
+
+GitHub is the default home for code, but it's a Microsoft-owned centralized service. Your repositories, commit history, issues, and CI/CD pipelines are all under someone else's control. For personal projects and private infrastructure, there's no reason to depend on it.
+
+## Solution
+
+[Gitea](https://gitea.com) is a lightweight, self-hosted Git service. It provides the full GitHub-style workflow — repositories, branches, pull requests, webhooks, and a web UI — in a single binary or Docker container that runs comfortably on low-spec hardware.
+
+---
+
+## Deployment (Docker)
+
+```yaml
+services:
+  gitea:
+    image: docker.gitea.com/gitea:latest
+    container_name: gitea
+    restart: unless-stopped
+    ports:
+      - "3002:3000"
+      - "222:22"    # SSH git access
+    volumes:
+      - ./gitea:/data
+    environment:
+      - USER_UID=1000
+      - USER_GID=1000
+      - GITEA__database__DB_TYPE=sqlite3
+```
+
+SQLite is fine for personal use. For team use, swap in PostgreSQL or MySQL.
+
+### Caddy reverse proxy
+
+```
+git.yourdomain.com {
+    reverse_proxy localhost:3002
+}
+```
+
+---
+
+## Initial Setup
+
+1. Browse to your Gitea URL — the first-run wizard handles configuration
+2. Set the server URL to your public domain
+3. Create an admin account
+4. Configure SSH access if you want `git@git.yourdomain.com` cloning
+
+---
+
+## Webhooks
+
+Gitea's webhook system is how automated pipelines get triggered on push. Example use case — auto-deploy a MkDocs wiki on every push:
+
+1. Go to repo → **Settings → Webhooks → Add Webhook**
+2. Set the payload URL to your webhook endpoint (e.g. `https://notes.yourdomain.com/webhook`)
+3. Set content type to `application/json`
+4. Select **Push events**
+
+The webhook fires on every `git push`, allowing the receiving server to pull and rebuild automatically. See [MajorWiki Setup & Pipeline](../../05-troubleshooting/majwiki-setup-and-pipeline.md) for a complete example.
+
+---
+
+## Migrating from GitHub
+
+Gitea can mirror GitHub repos and import them directly:
+
+```bash
+# Clone from GitHub, push to Gitea
+git clone --mirror https://github.com/user/repo.git
+cd repo.git
+git remote set-url origin https://git.yourdomain.com/user/repo.git
+git push --mirror
+```
+
+Or use the Gitea web UI: **+ → New Migration → GitHub**
+
+---
+
+## Why Not Just Use GitHub?
+
+For public open source — GitHub is fine, the network effects are real. For private infrastructure code, personal projects, and anything you'd rather not hand to Microsoft:
+
+- Full control over your data and access
+- No rate limits, no storage quotas on your own hardware
+- Webhooks and integrations without paying for GitHub Actions minutes
+- Works entirely over Tailscale — no public exposure required
+
+---
+
+## Tags
+
+#gitea #git #self-hosting #docker #linux #alternatives #vcs