fix: Replace Codeberg dependency with local Forgejo instance (#611)

- Add setup_forge() to bin/disinto: provisions Forgejo via Docker,
  creates admin + bot users (dev-bot, review-bot), generates API
  tokens, creates repo, and pushes code — all automated
- Rename env vars: CODEBERG_TOKEN→FORGE_TOKEN, REVIEW_BOT_TOKEN→
  FORGE_REVIEW_TOKEN, CODEBERG_REPO→FORGE_REPO, CODEBERG_API→
  FORGE_API, CODEBERG_WEB→FORGE_WEB, CODEBERG_BOT_USERNAMES→
  FORGE_BOT_USERNAMES (with backwards-compat fallbacks)
- Rename API helpers: codeberg_api()→forge_api(), codeberg_api_all()
  →forge_api_all() (with compat aliases)
- Add forge_url field to project TOML; load-project.sh derives
  FORGE_API/FORGE_WEB from forge_url + repo
- Update parse_repo_slug() to accept any host URL, not just codeberg
- Forgejo data stored under ~/.disinto/forgejo/ (not in factory repo)
- Update all 58 files: agent scripts, formulas, docs, site HTML

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

site/index.html

@@ -661,7 +661,7 @@
       <p>
         <strong>Bash scripts and Claude.</strong> No Kubernetes, no microservices,
         no SaaS dependencies. Runs on an 8GB VPS.
-        Point it at a <strong>Codeberg repo</strong> with a
+        Point it at a <strong>forge repo</strong> with a
         <strong>Woodpecker CI</strong> pipeline and it starts building.
       </p>
       <p>
@@ -691,8 +691,8 @@
       <div class="cta-links">
         <a href="/docs/quickstart">Quickstart</a>
         <a href="/docs/architecture">Architecture</a>
-        <a href="https://codeberg.org/johba/disinto">Browse the source</a>
-        <a href="https://codeberg.org/johba/disinto/issues">See active issues</a>
+        <a href="http://localhost:3000/johba/disinto">Browse the source</a>
+        <a href="http://localhost:3000/johba/disinto/issues">See active issues</a>
         <a href="/dashboard">Live dashboard</a>
       </div>
     </div>
@@ -702,7 +702,7 @@
       <div class="links">
         <a href="/docs/quickstart">quickstart</a>
         <a href="/docs/architecture">architecture</a>
-        <a href="https://codeberg.org/johba/disinto">source</a>
+        <a href="http://localhost:3000/johba/disinto">source</a>
         <a href="/dashboard">dashboard</a>
       </div>
       <div class="under-hood">