feat: Script Provisioning Provider extension (microsoft.azd.scripts)

[wbreza]

Description

Implements the Script Provisioning Provider extension (microsoft.azd.scripts) that enables shell script-based provisioning and teardown workflows in azd. This is a first-party extension that registers a scripts provisioning provider via gRPC.

Epic: #7733
Depends on: #7482 (provisioning provider framework)
Resolves: #7734, #7735, #7736

Architecture

The extension is a pure provisioning provider — no custom CLI commands, no MCP server. It registers via WithProvisioningProvider("scripts", factory) and implements the full azdext.ProvisioningProvider interface.

Key Components

Component	File	Purpose
Config parser	internal/provisioning/config.go	Typed config from infra.config with validation
EnvResolver	internal/provisioning/env_resolver.go	4-layer environment variable merging
ScriptExecutor	internal/provisioning/executor.go	Runs bash/pwsh scripts with merged env
OutputCollector	internal/provisioning/output_collector.go	Discovers/parses outputs.json files
Provider	internal/provisioning/provider.go	Full ProvisioningProvider implementation

User Configuration

infra:
  provider: scripts
  config:
    provision:
      - kind: sh
        run: scripts/setup.sh
        name: Setup Infrastructure
        env:
          AZURE_LOCATION: ${AZURE_LOCATION}
          RESOURCE_GROUP: rg-${AZURE_ENV_NAME}
    destroy:
      - kind: sh
        run: scripts/teardown.sh

Testing

• 25 unit tests covering config parsing, validation, env resolution, output collection, and executor
• All paths tested: happy path, error cases, edge cases, security (path traversal, absolute paths)
• Lint, spellcheck, copyright all pass

Checklist

• Extension compiles with go build
• Registers scripts provider via gRPC
• Config validation (missing run, absolute paths, path traversal, missing files, unknown kinds)
• Kind auto-inference from file extension (.sh -> sh, .ps1 -> pwsh)
• Shell -> Kind backward compatibility mapping
• Platform-specific overrides (Windows/Posix)
• 4-layer env var merging with ${EXPRESSION} substitution
• Output collection with 10MB size limit
• golangci-lint: 0 issues
• cspell: 0 issues
• All tests pass