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>

lib/hooks/on-pretooluse-guard.sh

@@ -5,7 +5,7 @@
 # Blocks:
 # - git push --force / -f to primary branch
 # - rm -rf targeting paths outside the worktree
-# - Direct Codeberg API merge calls (should go through phase protocol)
+# - Direct forge API merge calls (should go through phase protocol)
 # - Direct issue close calls (should go through phase protocol)
 # - git checkout / git switch to primary branch (stay on feature branch)
 # - FACTORY_ROOT access from worktrees (formula agents exempted)
@@ -88,7 +88,7 @@ if [ -n "$worktree_path" ] \
   fi
 fi
 
-# --- Guard 3: Direct Codeberg API merge calls ---
+# --- Guard 3: Direct forge API merge calls ---
 if printf '%s' "$command_str" | grep -qE '/pulls/[0-9]+/merge'; then
   printf 'BLOCKED: Direct API merge calls must go through the phase protocol. Push your changes and write PHASE:awaiting_ci — the orchestrator handles merges.\n'
   exit 2