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>

dev/AGENTS.md

@@ -19,8 +19,8 @@ while a dev-agent session is active on another issue.
 - `dev/phase-test.sh` — Integration test for the phase protocol
 
 **Environment variables consumed** (via `lib/env.sh` + project TOML):
-- `CODEBERG_TOKEN` — Dev-agent token (push, PR creation, merge) — use the dedicated bot account
-- `CODEBERG_REPO`, `CODEBERG_API` — Target repository
+- `FORGE_TOKEN` — Dev-agent token (push, PR creation, merge) — use the dedicated bot account
+- `FORGE_REPO`, `FORGE_API` — Target repository
 - `PROJECT_NAME`, `PROJECT_REPO_ROOT` — Local checkout path
 - `PRIMARY_BRANCH` — Branch to merge into (e.g. `main`, `master`)
 - `WOODPECKER_REPO_ID` — CI pipeline lookups