align CLI/UI payloads, export APIs, and fix beginner run docs

[rad1092]

Motivation

• Make the CLI match the beginner docs and provide a consistent bitnet-analyze UX with analyze and ui subcommands so newcomers can follow end-to-end instructions.
• Reuse prompt/payload generation between the CLI and the web UI so inline CSV from the UI is supported without duplicating logic.
• Export the actual public analysis helpers to avoid import-time issues and make functions available to tests and consumers.
• Clarify beginner docs to remove an unsupported --timeout example and provide a minimal, working run sequence.

Description

• Add subcommands and parsing helpers by introducing _build_parser() and main(argv: ...) in bitnet_tools.cli, and route legacy bare-CSV invocations into the analyze subcommand.
• Factor prompt construction into build_prompt(summary, question) and add build_analysis_payload_from_csv_text in bitnet_tools.analysis to support inline CSV analysis for the UI.
• Update bitnet_tools.__init__ to export build_analysis_payload, build_analysis_payload_from_csv_text, build_prompt, and summarize_rows.
• Wire the UI (bitnet_tools.web / ui/*) to call build_analysis_payload_from_csv_text and keep run_ollama error handling consistent.
• Update documentation files (BEGINNER_README.md, README.md) to remove the unsupported --timeout example, add minimal project install steps, and align troubleshooting with current CLI/UI behavior.
• Add/extend tests: new tests/test_cli.py and extended tests/test_analysis.py to cover legacy CLI invocation, UI serve routing (monkeypatched), and inline-CSV payload generation.

Testing

• Ran PYTHONPATH=. pytest -q and all tests passed (5 passed).
• Ran PYTHONPATH=. python -m bitnet_tools.cli --help which printed the CLI help for analyze and ui and exited successfully.
• CLI unit tests exercise the legacy-mode analyze routing and the ui serve hook (the serve call is monkeypatched in tests), and they passed as part of the test run.

---

Codex Task