feat(user_scan): add 50 username OSINT modules with metadata extraction

[kaifcodec]

Summary

Adds 50 new username OSINT detection modules across 8 categories with rich metadata extraction and strict dual-state verification.

• Dev (16): openeuler, odin_lang, openremote, opencraft, rakwireless, sensmetry, ngsolve, mgear_framework, mbse_capella, qorvo, plexim, sienci, spacecubics, msp360, lers, krakenrf
• Finance (13): pancakeswap, polygon, monero_space, moonbeam, moonwell, nimiq, pokt, scroll, ssv, stacks, reserve, inderes, mustachianpost
• Gaming (6): playhive, playboundless, playinzoi, pretendo, killerchesstraining, nikeagames
• Music (4): midibox, ikmultimedia, hifiguides, spinitron
• Community (8): forospyware, openfoodfacts, openhistoricalmap, intervals, keyboardmaestro, koishi, latranchee, liberland
• Learning (2): obsidian_zh, readlang
• Social (1): jami
• Creative (1): kustom

Highlights

• Zero false positives: dual-state verified against both existing and non-existent handles.
• Validates explicit not-found error payloads on HTTP 404 responses (error_type == 'not_found' / 'not be found' in errors).
• Extracts rich profile metadata (name, bio, location, website, trust_level, badges, joined) and profile media (avatar).
• Local CI passed: ruff check ., mypy user_scanner, and pytest.