bin: introduce mention-items subcommand

It is quite clunky to copy paste the output mention JSON into the items
subcommand. So this introduces a new subcommand "mention-items" which
automates that process. It will take an item from the mentions results
and send it to items. By default it is the first mention, but can does
accept an argument for another mention.

Test Plan: Ran locally. See this example:

  $ OPENCTX_CONFIG=../provider/devdocs/dist/bundle.js pnpm openctx mentions 'abort controller'
  #1 AbortController — https://devdocs.io/dom/abortcontroller
  #2 AbortController.abort — https://devdocs.io/dom/abortcontroller/abort
  #3 AbortController.signal — https://devdocs.io/dom/abortcontroller/signal
  #4 AbortController.constructor — https://devdocs.io/dom/abortcontroller/abortcontroller
  #5 ReadableByteStreamController.byobRequest — https://devdocs.io/dom/readablebytestreamcontroller/byobrequest

  $ OPENCTX_CONFIG=../provider/devdocs/dist/bundle.js pnpm openctx mention-items 'abort controller'
  #1 AbortController — https://devdocs.io/dom/abortcontroller
     - ai.content: (13659 characters)

bin/cli.mts

@@ -5,6 +5,7 @@ import { pathToFileURL } from 'url'
 import {
     type Client,
     type ClientConfiguration,
+    type Item,
     type Mention,
     type Range,
     createClient,
@@ -19,6 +20,7 @@ function usageFatal(message: string): never {
         'meta [providerUri]',
         'mentions <query> [providerUri]',
         'items <message> [providerUri] [mentionJSON]',
+        'mention-items <query> [mentionIndex] [providerUri]',
     ]
     for (const subcommand of subcommands) {
         console.error(`    ${subcommand}`)
@@ -80,7 +82,22 @@ async function subcommandItems(client: Client<Range>, args: string[]): Promise<v
     }
 
     const items = await client.items({ message, mention }, providerUri)
+    printItems(items)
+}
+
+async function subcommandMentionItems(client: Client<Range>, args: string[]): Promise<void> {
+    if (args.length === 0 || args.length > 3) {
+        usageFatal('Error: invalid args')
+    }
+    const [query, itemIndex, providerUri] = args
 
+    const mentions = await client.mentions({ query }, providerUri)
+    const mention = mentions[parseInt(itemIndex ?? 0)]
+    const items = await client.items({ mention }, mention.providerUri)
+    printItems(items)
+}
+
+function printItems(items: Item[]): void {
     if (process.env.OUTPUT_JSON) {
         console.log(JSON.stringify(items, null, 2))
     } else {
@@ -163,6 +180,11 @@ switch (subcommand) {
     case 'items':
         await subcommandItems(client, args)
         break
+    case 'mention-items':
+        await subcommandMentionItems(client, args)
+        break
     default:
         usageFatal(`Error: unrecognized subcommand ${JSON.stringify(subcommand)}`)
 }
+
+process.exit(0)