feat: add baseline plan and normalize numeric parsing (phase 0-1)

[rad1092]

Motivation

• Establish a repeatable baseline to compare pre/post changes for CSV analysis and lock representative fixtures for stable regression checks.
• Improve numeric parsing so the analyzer correctly recognizes common human-entered numeric formats (thousands separators, currency symbols, percent signs, and negative-by-parentheses).
• Add automated tests to validate numeric normalization and baseline fixture stability.

Description

• Add BASELINE_PLAN.md to document the baseline criteria and operational steps for pre/post comparison.
• Add three representative CSV fixtures under tests/fixtures/ (small_numeric.csv, mixed_formats.csv, missing_heavy.csv) to act as canonical inputs for baseline checks.
• Update bitnet_tools/analysis.py _to_float to normalize ,, ₩, $, €, £, % and to handle negative values written in parentheses before attempting float() parsing.
• Extend tests/test_analysis.py with test_to_float_normalizes_currency_comma_percent_parentheses and test_baseline_fixture_summaries_are_stable to assert normalization behavior and consistent summary outputs for the fixtures.

Testing

• Ran pytest -q, all tests passed (26 passed).
• Ran python -m bitnet_tools.cli doctor to validate environment diagnostics which executed successfully (reported local ollama absence).
• Ran python -m bitnet_tools.cli --help to verify CLI usage output which executed successfully.

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Codex Task

[chatgpt-codex-connector]

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