feat(init): devstack init workspace authoring wizard (spec 22)

[gustavobertoi]

Implements feature #14 / spec 22 — the workspace authoring front door. Pick shared engines, fill typed params, write a structurally-validated workspace.yaml. Pure config authorship: no lock, no Docker, no ledger.

Structured as the spec's "two faces, one builder" — the flag path and the Bubble Tea TUI both populate one scaffold.Inputs and call the same builder.

Foundation (internal/scaffold, fully unit-tested)

• EmitWorkspaceYAML — deterministic ordered goccy MapSlice emitter (sorted keys; params kept as strings so 16 never renders 16.0).
• BuildWorkspace / resolveParams — Provides-filter (only engines that declare provides: are shareable), drop-at-default, required-param fail-fast, store-seed.
• SanitizeName — CWD-basename → valid dsname.
• config.ValidateWorkspaceBytes — in-memory structural validation reusing the unexported structValidate/formatStructErr; a bad file is caught pre-write, not as a generate parse failure.

Flag path (internal/cli/init.go)

--name --service engine@ver --param svc.key=val --alias --project name=path[,git=url] --from-store --out --dry-run --force --json --no-input. Atomic no-clobber write (temp+rename, --force backs up), parent-workspace guard, RefuseWindowsMount.

Interactive face (internal/prompt + internal/cli/init_tui.go)

A Bubble Tea v2 wizard via charm.land/huh/v2: engine multi-select (store-seeded defaults), per-engine param forms pre-filled with template defaults, and a confirm screen previewing the YAML in a lipgloss box. Behind a shared prompt.IsInteractive gate so --json/--quiet/--no-input/non-TTY/CI always reach the builder without launching bubbletea. The charm v2 stack is pure-Go — CGO_ENABLED=0 4-target cross-build is clean and no v1 charm enters go.mod.

$ devstack init --name demo --service postgres@16 --service redis --service minio
# Generated by `devstack init` — edit freely; re-run is safe with --force.
apiVersion: devstack/v1
kind: Workspace
name: demo
shared:
  minio: { template: minio }
  postgres: { template: postgres, params: { version: "16" } }
  redis: { template: redis }

(emitted block-style; collapsed here for brevity)

Tests / verification

• internal/scaffold: golden bytes, determinism, int-not-float, Provides-filter, drop-at-default, required fail-fast, store-seed+override.
• internal/config: ValidateWorkspaceBytes pass/fail matrix.
• internal/cli: registered, happy-path → LoadWorkspaceOnly, deterministic, --json, --dry-run writes nothing, no-clobber + --force backup, parent-workspace refused, --from-store (never writes the store), non-TTY gate.
• internal/prompt: IsInteractive matrix.
• make ci + make determinism green; CGO=0 cross-build green.

Manual TTY check still needed: the interactive wizard's keyboard flow (verified compiling + gated; the builder it feeds is fully unit-tested).

Deferred (next)

• The internal/migrate consolidation onto EmitWorkspaceYAML (low-risk — migrate tests are structural; byte-shape pinned by the emit golden).
• A live two-pane (side-by-side) preview is a polish increment over the confirm-screen preview.

🤖 Generated with Claude Code