feat: enhanced recall scoring with recall_count and AI importance scoring

[rahilp]

• Add recall_count and importance_score columns to D1 via ALTER TABLE
• Update scoring formula to similarity × time_decay × (1 + log1p(recall_count))
• Increment recall_count fire-and-forget for entries shown in recall results
• Score new memories 1-5 via AI at capture time using ctx.waitUntil
• Add scoreImportance() for /capture (waitUntil) and remember tool (fire-and-forget)

Fixes #11

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	54.54%	330 / 605
🔵	Statements	54.54%	330 / 605
🔵	Functions	80.95%	17 / 21
🔵	Branches	84.72%	122 / 144

File Coverage

File	Stmts	Branches	Functions	Lines	Uncovered Lines
Changed Files
src/index.ts	54.54%	84.72%	80.95%	54.54%	57-58, 77-83, 98-99, 171-174, 193-196, 238-239, 336, 358-646, 745-746, 777-781, 787-788, 791-809

Generated in workflow #13 for commit 4379f40 by the Vitest Coverage Report Action