feat: Add Infisical adapter

[joelhooks]

Summary

Add Infisical as a secret source adapter for project-aware secrets.

Context

The SourceAdapter interface exists in internal/adapters/adapter.go. Vercel is implemented as reference.

Implementation

Files to create

• internal/adapters/infisical/infisical.go
• internal/adapters/infisical/infisical_test.go

Spec

type InfisicalAdapter struct {
    binary string // path to infisical CLI, default "infisical"
}

func New() *InfisicalAdapter
func (i *InfisicalAdapter) Pull(project, scope string) (map[string]string, error)
func (i *InfisicalAdapter) Name() string // returns "infisical"

CLI command

infisical export --projectId <project> --env <scope> --format dotenv

Register in cmd/secrets/adapter.go

case "infisical":
    return infisical.New(), nil

Test pattern

Follow internal/adapters/vercel/vercel_test.go - mock the CLI, test env parsing.

.secrets.json example

{
  "source": "infisical",
  "project": "proj_abc123",
  "scope": "production",
  "ttl": "1h"
}

Acceptance

• secrets env works with "source": "infisical"
• Tests pass without requiring actual Infisical CLI
• Error message when infisical CLI not installed