v0.3.0: overhaul — pricing fixes, tests, CI, docs

[Junaid2005]

Summary

Complete overhaul of afterquote — fixes 6 bugs that prevented the package from running, adds a test suite, modernizes CI, and updates docs.

Bug fixes

• OHLC anchoring — Impl_Open and Impl_Close now both seed from the base's last close (single anchor), fixing phantom gap at t=0 and 99% of invalid candles
• Inter-bar gaps — synthetic pricing now captures the gap between underlying's prev close and current open, fixing cumulative return error over long sessions
• Ticker validation — is_real_security() now actually rejects fake tickers instead of always returning True
• Exchange mappings — added 7 missing mappings (PCX, NYQ, AMS, GER, HKG, NSI, TOR)
• History fetch — pricing() passes end= to yfinance, fixing 0-row returns on newer yfinance versions
• Close-price lookup — widened window from ±5min to −30min/+5min, returns nearest bar
• No-data case — info() returns base's real close when underlying has no newer data, instead of crashing
• Leverage on High/Low — synthetic High/Low now apply the leverage factor (previously un-leveraged)

Added

• QuoteInfo dataclass for structured quote data
• pytest test suite (17 tests) with mocked yfinance — no network calls in CI
• Live end-to-end tests (skipped by default, --runlive)
• ruff (replaces black + pylint), mypy type checking
• Pre-commit hooks (ruff format, ruff check, mypy)
• CI tests on Python 3.10, 3.11, 3.12

Changed

• Pinned all dependencies with lower bounds
• CI installs from pyproject.toml (deleted stale requirements.txt)
• PyPI workflow: split build/publish, least-privilege permissions, official action
• Branch protection on main (requires PR + CI checks)

Commits

13 commits, one concern per commit. See commit history for details.