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>

.env.example

@@ -3,24 +3,33 @@
 # NEVER commit .env to the repo.
 
 # ── Per-project config ────────────────────────────────────────────────────
-# Project-specific settings (CODEBERG_REPO, PROJECT_REPO_ROOT, PRIMARY_BRANCH,
+# Project-specific settings (FORGE_REPO, PROJECT_REPO_ROOT, PRIMARY_BRANCH,
 # WOODPECKER_REPO_ID) now live in projects/*.toml — see projects/harb.toml
 # for an example. Do NOT set them here; they leak into every session.
 
+# ── Forge (Forgejo) ─────────────────────────────────────────────────────
+# Base URL for the local Forgejo instance. disinto init provisions this.
+FORGE_URL=http://localhost:3000
+
 # ── Auth tokens ───────────────────────────────────────────────────────────
 # Dev-agent token: push branches, create PRs, merge PRs.
-# Use the dedicated bot account (e.g. factory_bot / disinto_dev).
+# Use the dedicated bot account (e.g. dev-bot).
 # Branch protection: this account must be in the merge whitelist.
-CODEBERG_TOKEN=
+FORGE_TOKEN=
 
 # Review-agent token: post review comments and submit formal approvals.
-# Use the human/admin account (e.g. johba).
+# Use the review bot account (e.g. review-bot).
 # Branch protection: this account must be in the approvals whitelist.
-REVIEW_BOT_TOKEN=
+FORGE_REVIEW_TOKEN=
 
-# Comma-separated Codeberg usernames to filter from issue comments.
+# Comma-separated forge usernames to filter from issue comments.
 # The token owner is auto-detected; add extra bot accounts here if needed.
-CODEBERG_BOT_USERNAMES=
+FORGE_BOT_USERNAMES=
+
+# ── Backwards compatibility ───────────────────────────────────────────────
+# If CODEBERG_TOKEN is set but FORGE_TOKEN is not, env.sh falls back to
+# CODEBERG_TOKEN automatically (same for REVIEW_BOT_TOKEN, CODEBERG_REPO,
+# CODEBERG_BOT_USERNAMES). No action needed for existing deployments.
 
 # ── Woodpecker CI ─────────────────────────────────────────────────────────
 WOODPECKER_TOKEN=