feat: task listing wihtout no-intractive (--list and --json flags)

docs/listing.md

@@ -0,0 +1,188 @@
+# Task Listing
+
+`vp run --list` shows all available tasks across the workspace and exits without running anything. Combined with `--json`, it produces machine-readable output for CI pipelines, shell completion, and tooling integration.
+
+`vp run --help` displays a hint about the `--list` flag so that users (and AI agents) can discover it.
+
+## `--list` / `-l`
+
+```sh
+vp run --list
+vp run -l        # short alias
+```
+
+Prints a flat list of all tasks with their commands:
+
+```
+@vrowzer/fs#build           tsdown
+@vrowzer/fs#build:docs      typedoc --excludeInternal
+@vrowzer/example-vue#build  vite build
+@vrowzer/example-vue#dev    vite
+test:unit:vite              pnpm run --color "/^test:unit:vite:/"
+test:unit:vrowzer           vitest run --project vrowzer:unit
+typecheck                   pnpm -r --if-present typecheck
+```
+
+Tasks from named packages use the `package#task` format. Tasks from the workspace root (when the root `package.json` has no `name` field) are shown without a prefix.
+
+The flag is mutually exclusive with `--last-details`.
+
+## `--json`
+
+```sh
+vp run --list --json
+```
+
+Outputs the task list as a JSON array. Requires `--list`.
+
+```json
+[
+  {
+    "package": "@vrowzer/fs",
+    "task": "build",
+    "command": "tsdown",
+    "packagePath": "packages/fs"
+  },
+  {
+    "package": "@vrowzer/fs",
+    "task": "build:docs",
+    "command": "typedoc --excludeInternal",
+    "packagePath": "packages/fs"
+  },
+  {
+    "package": "@vrowzer/example-vue",
+    "task": "build",
+    "command": "vite build",
+    "packagePath": "examples/vue"
+  },
+  {
+    "package": "@vrowzer/example-vue",
+    "task": "dev",
+    "command": "vite",
+    "packagePath": "examples/vue"
+  },
+  {
+    "package": null,
+    "task": "test:unit:vite",
+    "command": "pnpm run --color \"/^test:unit:vite:/\"",
+    "packagePath": "."
+  },
+  {
+    "package": null,
+    "task": "test:unit:vrowzer",
+    "command": "vitest run --project vrowzer:unit",
+    "packagePath": "."
+  },
+  {
+    "package": null,
+    "task": "typecheck",
+    "command": "pnpm -r --if-present typecheck",
+    "packagePath": "."
+  }
+]
+```
+
+The `package` field is `null` when the task belongs to a workspace root whose `package.json` has no `name` field. `packagePath` is the package directory relative to the workspace root.
+
+## Filtering
+
+`--list` works with the standard package filter flags to scope the output:
+
+```sh
+vp run --list -r                         # all packages (same as bare --list)
+vp run --list -F app                     # only tasks in "app" package
+vp run --list --filter "./packages/*"    # packages under packages/
+vp run --list -w                         # workspace root only
+```
+
+Without any filter flag, `--list` shows tasks from all packages in the workspace.
+
+## Use Cases
+
+### Onboarding
+
+New developers can quickly see what tasks are available across the monorepo:
+
+```sh
+vp run --list
+```
+
+### CI/CD Task Verification
+
+Check whether a task exists before running it:
+
+```sh
+if vp run --list --json | jq -e '.[] | select(.task == "typecheck")' > /dev/null; then
+  vp run typecheck
+fi
+```
+
+### Shell Completion
+
+Dynamically populate tab-completion candidates:
+
+```sh
+# zsh completion function
+_vp_run_tasks() {
+  local tasks=$(vp run --list --json | jq -r '.[].task')
+  compadd $tasks
+}
+```
+
+### AI/LLM Integration
+
+LLMs and AI agents can retrieve structured task information to understand the project:
+
+```sh
+vp run --list --json
+# Returns task names, commands, and package paths as structured JSON
+```
+
+### Documentation Generation
+
+Generate a Markdown task inventory from JSON:
+
+```sh
+vp run --list --json | jq -r '.[] | "- `\(.package // "(root)")#\(.task)`: \(.command)"'
+```
+
+### Package-Scoped Inspection
+
+Inspect tasks for a specific package or directory:
+
+```sh
+# Tasks in the "app" package
+vp run --list -F app
+
+# Tasks under the infra directory
+vp run --list --filter "./infra/*"
+```
+
+## Flag Interactions
+
+| Combined with    | Behavior                                   |
+| ---------------- | ------------------------------------------ |
+| `--json`         | Output as JSON array instead of plain text |
+| `-r`             | Show all packages (same as bare `--list`)  |
+| `-F <pattern>`   | Scope to matching packages                 |
+| `--filter <pat>` | Scope to matching packages                 |
+| `-w`             | Show workspace root tasks only             |
+| `-t`             | Show current package and transitive deps   |
+| `--last-details` | **Error** — mutually exclusive             |
+
+`--json` without `--list` is an error.
+
+## Discoverability
+
+`vp run --help` includes a hint about the `--list` flag so that users and AI agents can discover it without prior knowledge:
+
+```
+Options:
+  -l, --list        List all available tasks and exit without running
+      --json        Output task list as JSON (requires --list)
+  ...
+
+Tip: use `--list` to see all available tasks.
+```
+
+This hint is rendered via clap's `after_help` attribute on the `run` subcommand.