feat: entity enrichment observations from Granola importer
Extend seed_entities() to accept optional observations list per entity
dict. After entity creation/resolution, adds observations via
add_observation() with dedup against existing content.
Update Granola importer to build observation strings from parsed
participant data (title, company, LinkedIn) and pass them through
seed_entities(). Format: "fact (via Granola, YYYY-MM-DD)".
Implements product decision: records/decisions/2026-03-14-entity-enrichment-from-imports.md
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>