#553 packages: drop moss-cli, ship license text and SPDX metadata

Fixes MOS-610. Part of MOS-614.

moss-cli releases to PyPI from moss-sdks-internal under PolyForm Shield, like every other SDK package since #546. The BSD copy here, and the workflow that could publish it under the same name, go away. The packages here that declare MIT or BSD 2-Clause now ship that license text and declare it in their metadata.

moss-cli (MOS-610)

• Removes packages/moss-cli and .github/workflows/publish-moss-cli.yml, and drops moss-cli from scripts/release.sh.
• The README feature list links the CLI docs instead of the folder. AGENTS.md drops its entries.
• The PYPI_API_TOKEN secret stays, since 17 other publish workflows use it. If it is an account-wide token, a project-scoped token per package (or Trusted Publishing) would stop it from uploading moss-cli.

License text and metadata (MOS-614)

• Adds a BSD 2-Clause LICENSE to every packages/moss-data-connector/* connector and _template, and to sdks/go/sdk and sdks/go/bindings. The Go copies match the root text, so the module zips no longer depend on the root file.
• Adds an MIT LICENSE to examples/cookbook/langchain and packages/vitepress-plugin-moss, as each already declares, and sets the plugin's author.
• The connectors, langchain-moss and {elevenlabs,sim,strands-agents,vapi,pipecat}-moss declare a PEP 639 license expression and license-files. This needs setuptools 77 or hatchling 1.27, and drops the connectors' License :: classifiers, which PEP 639 does not allow next to an expression.
• pipecat-moss adds the Moss copyright line beside Daily's in LICENSE and the source headers, uses the SPDX id BSD-2-Clause, and replaces a control byte in one header.

New LICENSE files use the root Copyright (c) 2026, Moss Team line, as the packages added this year do. MOS-623 settles the holder string. The LICENSE files that #552 edits are untouched. No version bumps here; patch releases follow separately.

🤖 Generated with Claude Code

Summary by CodeRabbit

• Removals

  • Removed the Moss CLI package, including commands for indexes, documents, queries, jobs, profiles, synchronization, validation, completions, and version information.
  • Removed CLI release automation, documentation, changelog, configuration, and related tests.
  • Removed the CLI from package release examples.

• Documentation

  • Updated the main Features section to link to the Moss CLI documentation.

• Licensing & Packaging

  • Added or clarified license files and SPDX metadata across integrations and connectors.
  • Raised minimum build-tool requirements for several packages.