feat(moss-cli): add mapped CSV/JSON bulk import

[Mahin2076]

Pull Request Checklist

• I have read the CONTRIBUTING guide.
• I have updated the documentation.
• My code follows the style guidelines of this project.
• I have performed a self-review of my own code.
• I have added tests that prove the feature works.
• New and existing tests pass locally, except for two pre-existing shell-completion failures described below.

Description

Adds a discoverable bulk-import workflow for CSV, JSON, and JSONL files whose source columns do not already use Moss's id and text names.

• Adds the requested moss documents import command and the shorter moss doc import form.
• Supports --id-column, --text-column, repeatable --metadata-column, and comma-separated --metadata-columns mappings.
• Reuses the existing authentication, profile, upsert, wait, timeout, JSON-output, and index-completion behavior.
• Validates mapped files before creating the client, with row-specific errors for missing or blank required values.
• Preserves the existing standard document format, including metadata objects, custom embeddings, JSON wrappers, JSONL, and stdin input.
• Handles quoted multiline CSV fields without retaining an additional copy of every parsed row.
• Documents the new workflow and adds focused parser and no-network CLI coverage.

moss documents import products -f products.csv \
  --id-column sku \
  --text-column description \
  --metadata-column category \
  --metadata-column price \
  --upsert --wait

Fixes #379

Testing

• pytest packages/moss-cli/tests/test_documents_import.py -q — 29 passed on Python 3.13 and 3.14
• Repeated the focused suite with Typer 0.9.0 (declared minimum) and Typer 0.26.8 — 29 passed on each
• ruff check . --extend-exclude '**/*.ipynb'
• mypy packages/moss-cli/src/moss_cli/documents.py packages/moss-cli/src/moss_cli/commands/doc.py --ignore-missing-imports
• black --check and isort --check-only on changed Python files
• Python 3.10 grammar check on changed Python files
• Built both sdist and wheel; twine check passed for both
• Clean-wheel smoke test: package import and moss documents import --help passed

The full Moss CLI suite reports 57 passed and 2 failed under the latest Typer. The same two untouched shell-completion tests (test_completions_bash_outputs_script and test_completions_zsh_outputs_script) also fail on origin/main in the same environment because Typer's completion API changed; this PR does not alter that code.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature which changes existing behavior)
• Documentation update

[CLAassistant]

All committers have signed the CLA.

[Copilot]

Pull request overview

This PR adds a bulk-import workflow to the Moss CLI that supports CSV/JSON/JSONL inputs where the source data doesn’t use the standard id / text field names, addressing the usability request in #379 and making non-code document loading more discoverable.

Changes:

• Added moss documents import (and moss doc import) to bulk-import documents with --id-column, --text-column, and metadata-column mapping.
• Enhanced the document loader to support column mapping, better CSV handling (including multiline quoted fields), and more actionable validation errors.
• Added focused tests plus documentation and changelog entries describing the new workflow.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
packages/moss-cli/tests/test_documents_import.py	Adds comprehensive parser + CLI coverage for mapped imports across CSV/JSON/JSONL and stdin.
packages/moss-cli/src/moss_cli/main.py	Registers documents as an alias command group for doc to make the feature discoverable.
packages/moss-cli/src/moss_cli/documents.py	Implements mapping-aware parsing/validation for CSV/JSON/JSONL while preserving legacy document formats.
packages/moss-cli/src/moss_cli/commands/doc.py	Adds the import command and shared submission logic; parses mapping flags and validates input before client creation.
packages/moss-cli/README.md	Documents the new import workflow and examples for mapped column usage.
packages/moss-cli/CHANGELOG.md	Notes the new bulk import feature in Unreleased.

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