chore(dev): improve local dev experience

[jaeyunha]

What

Improves the local dev workflow with four independent changes:

• Go API hot reload — apps/api/.air.toml + scripts/dev-api.sh + make dev-api. Rebuilds ./cmd/api on save (uses air, falls back to go run if not installed).
• make dev-full — one command for the full host stack: Docker services + migrations, Go API (:7016), and web (:7015) together.
• lefthook pre-commit — auto-formats staged files (biome --write, gofmt -w). Installs on pnpm install. Not a substitute for make check.
• .vscode/ configs — shared format-on-save settings, recommended extensions, and Go/Next.js debug launch configs.
• make codegen — regenerate sqlc queries + Go OpenAPI stubs + TS SDK in one step.

Why

• Go API had zero hot reload — every change meant a full Docker rebuild or manual restart.
• Host-dev required 3–4 manual terminals and CONTRIBUTING never documented starting the Go API, so new devs hit silent /api/* 502s.
• No pre-commit enforcement; make check was discipline-only.
• No shared editor config.

Docs

• CONTRIBUTING.md: fixed the host-dev path (added the missing API-start step) and documented make dev-full / make codegen.
• AGENTS.md + CLAUDE.md: added agent-must-know command notes.

Verification

• Scripts pass bash -n; make targets parse.
• go build ./cmd/api compiles (air build cmd valid).
• lefthook hook installed; lefthook validate passes; pre-commit ran clean on this commit.
• New JSON files pass Biome.

🤖 Generated with Claude Code

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Resolve the compose file path before starting dev services

make dev-full stops at this step because pnpm --filter @exponential/web dev-services runs the web package script with apps/web as its working directory, and that script invokes docker compose -f docker-compose.yml; there is no compose file under apps/web (it lives at the repo root), so Postgres/Redis never start and the API/web processes are not launched. Use a root-relative/absolute compose path or run the service bootstrap from the repo root.

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