docs(FR-2788): add LICENSE and README to backend.ai-client

[yomybaby]

Resolves #7195(FR-2788)

Epic: FR-2792

Summary

Adds the standard publishability files to the backend.ai-client workspace package, which was just extracted as a standalone package in #6614 (FR-2529).

• packages/backend.ai-client/LICENSE — full LGPL-3.0-or-later text from gnu.org with a Copyright (C) 2024 Lablup Inc. header. package.json already declares "license": "LGPL-3.0-or-later"; the file was missing.
• packages/backend.ai-client/README.md — minimum publishable README:
  • One-line description matching package.json.description
  • Installation snippet (pnpm add / npm install)
  • Quickstart with Client + ClientConfig using the real constructor signatures (ClientConfig(accessKey, secretKey, endpoint, connectionMode), Client(config, agentSignature)) and the actual client.keypair.list() / client.computeSession.list() APIs
  • Runtime support note: ESM-only, Node ≥18, modern browsers
  • Repo + issues tracker links
  • License pointer

Out of scope

• package.json exports / main / publishConfig polish (handled by FR-2789)
• API reference (TypeDoc)
• README translations

Test plan

• packages/backend.ai-client/LICENSE exists with full LGPL-3.0-or-later body
• packages/backend.ai-client/README.md renders correctly (Markdown only; no executable code)
• Quickstart uses real constructor signatures and resource methods (verified against src/client.ts, src/client-config.ts, src/resources/keypair.ts, src/resources/compute-session.ts)
• No changes to package.json (kept scope to docs)
• bash scripts/verify.sh: Relay / Lint / Format pass. TypeScript errors are pre-existing in client.ts and unrelated to this docs-only PR (confirmed against the pre-change baseline).

[yomybaby]

• docs(FR-2788): add LICENSE and README to backend.ai-client #7202 👈 (View in Graphite)
• main

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[Copilot]

Pull request overview

Adds the missing “publishability” documentation artifacts for the extracted packages/backend.ai-client workspace package so it can be distributed with standard metadata files.

Changes:

• Added packages/backend.ai-client/README.md with installation, quickstart, runtime support, and links.
• Added packages/backend.ai-client/LICENSE intended to contain LGPL-3.0-or-later license text.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
packages/backend.ai-client/README.md	Introduces minimal package README with installation + quickstart usage.
packages/backend.ai-client/LICENSE	Adds an LGPL-3.0-or-later license file for package distribution.

Comments suppressed due to low confidence (1)

packages/backend.ai-client/LICENSE:168

• The LGPL-3.0-or-later text in this LICENSE file appears truncated: it ends immediately after section 6 without the usual closing text (e.g., "END OF TERMS AND CONDITIONS" and the "How to Apply These Terms..." appendix). For legal/publishability purposes, please include the complete, unmodified LGPL v3 license text (aside from the optional project copyright header).

  6. Revised Versions of the GNU Lesser General Public License.

  The Free Software Foundation may publish revised and/or new versions
of the GNU Lesser General Public License from time to time. Such new
versions will be similar in spirit to the present version, but may
differ in detail to address new problems or concerns.

  Each version is given a distinguishing version number. If the
Library as you received it specifies that a certain numbered version
of the GNU Lesser General Public License "or any later version"
applies to it, you have the option of following the terms and
conditions either of that published version or of any later version
published by the Free Software Foundation. If the Library as you
received it does not specify a version number of the GNU Lesser
General Public License, you may choose any version of the GNU Lesser
General Public License ever published by the Free Software Foundation.

  If the Library as you received it specifies that a proxy can decide
whether future versions of the GNU Lesser General Public License shall
apply, that proxy's public statement of acceptance of any version is
permanent authorization for you to choose that version for the
Library.