Add DEVELOPMENT.md and doctor task for new workstation setup (#237)

Adds a development setup guide covering Homebrew-based tool installation,
common tasks, and project structure. Adds a `task doctor` command to
verify all required tools are installed.

Author: straubt1

DEVELOPMENT.md

@@ -0,0 +1,123 @@
+# Development Setup
+
+This guide covers setting up a macOS workstation for TFx development from scratch.
+
+## Prerequisites
+
+Install [Homebrew](https://brew.sh) if you don't have it:
+
+```bash
+/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
+```
+
+## Install Dependencies
+
+Install the core tools:
+
+```bash
+brew install go goreleaser go-task
+```
+
+| Tool | Purpose |
+|---|---|
+| `go` | Go compiler and toolchain |
+| `goreleaser` | Cross-platform builds and releases |
+| `go-task` | Task runner (provides the `task` command) |
+
+### Optional
+
+```bash
+brew install node   # only needed for serving the docs site locally (task serve-docs)
+```
+
+Verify everything is installed:
+
+```bash
+task doctor
+```
+
+## Clone and Build
+
+```bash
+git clone https://github.com/straubt1/tfx.git
+cd tfx
+go mod download
+task go-build
+./tfx version
+```
+
+## Common Tasks
+
+Run `task --list` to see all available tasks. Key ones:
+
+| Task | Description |
+|---|---|
+| `task doctor` | Verify all required tools are installed |
+| `task go-build` | Build the `tfx` binary for local development |
+| `task go-build-all` | Cross-platform snapshot build via goreleaser |
+| `task test` | Run unit tests |
+| `task test-all` | Run unit + integration tests |
+| `task go-upgrade` | Upgrade Go toolchain and all module dependencies |
+| `task serve-docs` | Serve the documentation site locally |
+| `task release-dry-run` | Simulate the full release pipeline locally |
+
+## Upgrading Dependencies
+
+To upgrade Go, goreleaser, and all module dependencies:
+
+```bash
+task go-upgrade
+```
+
+This will:
+1. Upgrade `go` and `goreleaser` via Homebrew
+2. Update `go.mod` to the installed Go version
+3. Upgrade all module dependencies to their latest versions
+4. Run `go mod tidy` to clean up
+
+## Configuration for CLI / Integration Tests
+
+TFx requires a TFE/HCP Terraform instance for integration tests. Create `secrets/.env-int`:
+
+```bash
+mkdir -p secrets
+cat > secrets/.env-int << 'EOF'
+TFE_HOSTNAME=app.terraform.io
+TFE_TOKEN=your-api-token
+TFE_ORGANIZATION=your-org
+EOF
+```
+
+Then run integration tests:
+
+```bash
+task test-integration-data
+task test-integration-cmd
+```
+
+## Project Structure
+
+```
+cmd/          # Cobra command handlers
+  flags/      # Per-command flag structs
+  views/      # Output/rendering for each command
+client/       # TFE API client wrapper
+data/         # Data fetching layer (API calls + business logic)
+output/       # Output system (tables, JSON, spinner, logger)
+tui/          # Bubble Tea TUI
+integration/  # Integration tests
+pkg/file/     # File utilities
+version/      # Version info (injected at build time)
+```
+
+## Releasing
+
+See the release tasks:
+
+```bash
+task release:patch   # bugfixes (x.y.Z+1)
+task release:minor   # new features (x.Y+1.0)
+task release:major   # breaking changes (X+1.0.0)
+```
+
+Always update `CHANGELOG.md` before cutting a release.

Taskfile.yml

@@ -1,6 +1,40 @@
 version: '3'
 
 tasks:
+  doctor:
+    desc: Verify all required development tools are installed
+    silent: true
+    cmds:
+      - |
+        OK=true
+        check() {
+          if command -v "$1" &>/dev/null; then
+            printf "  ✓ %-14s %s\n" "$1" "$($1 $2 2>&1 | head -1)"
+          else
+            printf "  ✗ %-14s not found — install with: %s\n" "$1" "$3"
+            OK=false
+          fi
+        }
+        echo ""
+        echo "  TFx Development Environment"
+        echo "  ────────────────────────────"
+        check go    "version"        "brew install go"
+        check goreleaser "--version"  "brew install goreleaser"
+        check task   "--version"     "brew install go-task"
+        echo ""
+        if command -v node &>/dev/null; then
+          printf "  ✓ %-14s %s  (optional — docs site)\n" "node" "$(node --version 2>&1)"
+        else
+          printf "  · %-14s not installed  (optional — only for: task serve-docs)\n" "node"
+        fi
+        echo ""
+        if [ "$OK" = true ]; then
+          echo "  All tools installed."
+        else
+          echo "  Install missing tools:  brew install go goreleaser go-task"
+        fi
+        echo ""
+
   go-build:
     desc: Build Go binary (development build with git metadata)
     cmds: