chore(task): archive 08-11-interactive-area-cli

.trellis/tasks/archive/2026-08/08-11-interactive-area-cli/design.md

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+# Interactive Area Build CLI Design
+
+## Scope
+
+Add a zero-dependency terminal interface for choosing an area configuration and one or more existing
+pipeline stages. It delegates execution to the existing `build-area.js` entry point and does not change
+the pipeline's stage implementations or generated artifacts.
+
+## Architecture
+
+```text
+npm run build
+  -> scripts/interactive-build.js
+  -> terminal menus (TTY only)
+  -> node scripts/build-area.js --config <area> --stages <canonical-list>
+  -> existing build pipeline
+```
+
+Extract the stage metadata, aliases, canonical execution order, and mutual-exclusion validation from
+`build-area.js` into a CommonJS module under `scripts/lib/`. Both the interactive script and
+`build-area.js` consume this module, making the menu's options the same source of truth as execution.
+
+## Interaction
+
+1. Discover and sort `config/areas/*.json`; present a single-select area menu.
+2. Present a multi-select stage menu with descriptions and selection markers.
+3. Arrow keys move focus, space toggles, enter confirms, and Ctrl-C/Escape cancels.
+4. The menu prevents or reports the `intermediates`/`reimport` conflict before spawning a build.
+5. The selected stages are normalized to canonical pipeline order and passed to `build-area.js`.
+
+The interactive entry requires both stdin and stdout to be TTYs. Otherwise it exits non-zero with an
+instruction to use `npm run build:area -- --config ... --stages ...`; it never falls back to defaults.
+
+## Compatibility
+
+- `build-area.js` remains the execution owner and keeps its CLI flags and defaults.
+- `npm run build:area` continues to invoke it directly.
+- `npm run build` changes only from the former default build alias to the interactive wrapper.
+- A successful `cesium` selection continues to generate preview output through the existing behavior;
+  selecting `preview` explicitly remains valid for a standalone preview refresh.
+
+## Validation
+
+- Unit-test stage normalization, alias expansion, ordering, and mutual exclusion.
+- Unit-test config discovery and non-TTY refusal without launching a build.
+- Syntax-check both CLI entry scripts.
+- Manually exercise the menu in a TTY: select an area, select unordered stages, confirm the canonical
+  command preview, and cancel before execution.
+
+## Risks And Rollback
+
+Raw terminal input must always restore raw mode and cursor state on confirmation, cancellation, and
+errors. The wrapper only spawns the unchanged existing build script, so rollback is deleting the new
+interactive entry and restoring the `build` package script.