chore: replace docker-compose with nix process-compose for dev deps

[Lakshyyaa]

Follows GaloyMoney/es-entity#140, GaloyMoney/job#114, and GaloyMoney/cala#729. Migrates obix's dev loop off Docker/podman onto a Nix-managed process-compose Postgres, with per-worktree port allocation so multiple checkouts run their dev DB in parallel. No Docker required for sqlx-prepare, integration tests, or make start-deps.

Changes

• flake.nix: add process-compose-flake input; dev-env (CRC32-of-cwd → dynamic PGPORT/PG_CON), pg-start (root setpriv drop + bounded readiness), setup-db-dev, mkPg/nix-deps-base; rewrite nextest-runner off podman (XDG_CONFIG_HOME, _pgdev, bounded readiness wait, synchronous migrations); drop docker-compose/podman/podman-compose, add process-compose; export dev-env/setup-db-dev/nix-deps-base packages+apps; devShell shellHook evals dev-env
• Makefile: start-deps/clean-deps/setup-db/reset-deps via process-compose + bounded wait; migrations folded into start-deps
• tests/helpers.rs: read PG_CON from env (dynamic port) instead of hardcoded :5432
• ci/pipeline.yml: drop privileged: true (no container engine needed in CI)
• remove docker-compose.yml, nix/podman-runner.nix
• .gitignore: add .nix-deps/

Notes

• obix has no book/, so the runner is es-entity's minus the mdbook steps. Migrations live at repo root (job_setup, obix_setup), so setup-db-dev runs a plain sqlx migrate run (no cd, unlike cala).
• The .sqlx cache only covers lib queries; the test-only queries (TRUNCATE persistent_outbox_events, …) are not cached, so nextest-runner compiles online against the live migrated PG. SQLX_OFFLINE=true stays in commonArgs only for the offline crane nix flake check.
• Supersedes the stale chore: replace docker-compose with nix process-compose for dev deps #62, which used a static :5432 port and didn't touch .gitignore/ci/pipeline.yml/tests/helpers.rs (so it didn't solve multi-worktree). Mirrors how job#114 superseded its stale same-named branch.

Verification (local)

• nix run .#dev-env → consistent per-worktree derivation (PGPORT=30800, matching PG_CON) ✅
• alejandra -qc flake.nix ✅
• make start-deps → PG up via process-compose on derived port, both migrations applied ✅
• cargo nextest run --workspace → 18 passed, 0 failed (online against PG_CON) ✅
• make clean-deps → torn down, .nix-deps/ removed ✅

🤖 Generated with Claude Code

---

Note

Medium Risk
Touches CI test bootstrap and DB connectivity for all integration tests; behavior change is intentional but failures would block dev and CI until deps are healthy.

Overview
Replaces Docker/podman dev Postgres with Nix process-compose and a local pg-start helper, so make start-deps, migrations, and CI tests no longer need a container engine.

flake.nix adds process-compose-flake, obix-dev-env (CRC32 of checkout path → per-worktree PGPORT / PG_CON), nix-deps-base for core-pg, setup-db-dev, and rewrites nextest-runner to start PG via process-compose (root setpriv to _pgdev, bounded readiness, sync migrations). Dev shell shellHook evals dev-env. Podman/docker-compose tooling is removed.

Makefile wires start-deps / clean-deps / reset-deps through nix run and folds migrations into start-deps. tests/helpers.rs uses PG_CON from the environment instead of a fixed :5432. CI drops privileged: true. docker-compose.yml and nix/podman-runner.nix are deleted; .gitignore ignores .nix-deps/.

^{Reviewed by Cursor Bugbot for commit c4cdb6b. Bugbot is set up for automated code reviews on this repo. Configure here.}

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

^{❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.}

^{Reviewed by Cursor Bugbot for commit c5b1761. Configure here.}