refactor: split supervisor into infra + per-project, make poll scripts config-driven

Supervisor split (#26):
- Layer 1 (infra): P0 memory, P1 disk, P4 housekeeping — runs once, project-agnostic
- Layer 2 (per-project): P2 CI/dev-agent, P3 PRs/deps — iterates projects/*.toml
- Adding a new project requires only a new TOML file, no code changes

Poll scripts accept project TOML arg (#27):
- dev-poll.sh, review-poll.sh, gardener-poll.sh accept optional project TOML as $1
- env.sh loads PROJECT_TOML if set, overriding .env defaults
- Cron: `dev-poll.sh projects/versi.toml` targets that project

New files:
- lib/load-project.sh: TOML to env var loader (Python tomllib)
- projects/versi.toml: current project config extracted from .env

Backwards compatible: scripts without a TOML arg fall back to .env config.

Closes #26, Closes #27

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

lib/env.sh

@@ -19,6 +19,11 @@ fi
 export PATH="${HOME}/.local/bin:${HOME}/.foundry/bin:${HOME}/.nvm/versions/node/v22.20.0/bin:/usr/local/bin:/usr/bin:/bin:${PATH}"
 export HOME="${HOME:-/home/debian}"
 
+# Load project TOML if PROJECT_TOML is set (by poll scripts that accept project arg)
+if [ -n "${PROJECT_TOML:-}" ] && [ -f "$PROJECT_TOML" ]; then
+  source "${FACTORY_ROOT}/lib/load-project.sh" "$PROJECT_TOML"
+fi
+
 # Codeberg token: env var > ~/.netrc
 if [ -z "${CODEBERG_TOKEN:-}" ]; then
   CODEBERG_TOKEN="$(awk '/codeberg.org/{getline;getline;print $2}' ~/.netrc 2>/dev/null || true)"