Add Wikipedia Scout pipeline scaffolding

[artvandelay]

Motivation

• Provide a lightweight scaffold to ingest Wikimedia EventStreams recentchange events and persist them for downstream analysis.
• Enable extraction and analysis of edit diffs by adding diff parsing, term extraction, and spike detection utilities to surface anomalous term activity.
• Expose a simple reporting path to render term spike digests for review and alerting workflows.

Description

• Add a new wiki_scout package with modules config.py, ingest.py, storage.py, diffs.py, terms.py, spikes.py, report.py, and __init__.py that wire the pieces together.
• Implement EventStreamClient and consume_recentchange to stream events and write allowed events to SQLite using connect, init_db, and insert_recentchange.
• Implement diff utilities fetch_diff_html and parse_diff_text, term extraction helpers tokenize and extract_terms, and spike utilities robust_z_score, ratio_spike, and window_range.
• Add reporting helpers build_digest and render_markdown that read spike_events from the database and produce a markdown digest.

Testing

• No automated tests were run.

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Codex Task