fix(memory,hooks): add structural pagination and canonical Ruflo resolution

[stuinfla]

Summary

• add validated memory list --offset pagination and opt-in JSON --page-info metadata (total, nextOffset, hasMore)
• fail closed when pagination reports rows remaining but returns no progress
• make plugin hooks prefer the canonical global ~/.npm-global/bin/ruflo, then PATH, without downloading a private npx copy
• update the ruflo-core contract and plugin patch version to describe the enforced hook behavior

Why

Cross-session continuity needs a structural way to enumerate every AgentDB row; a fixed first-page listing can silently omit older checkpoints. Hook invocations also must not create a second Ruflo installation whose behavior can diverge from the globally managed CLI.

Verification

Base: 3c99b1c84a25948c42a163253bac6effed5fbbbb
Head: fd42708592df971500f75fb9882c0bd44faf7014

• pnpm exec vitest run v3/@claude-flow/cli/__tests__/memory-list-pagination-structural.test.ts — 7/7 passed
• bash plugins/ruflo-core/scripts/smoke.sh — 11/11 passed
• node plugins/ruflo-core/scripts/test-hooks.mjs "node $PWD/v3/@claude-flow/cli/bin/cli.js" — 26/26 passed
• git diff --check origin/main...HEAD — passed
• Gitleaks over the exact three-commit range — no leaks found

Scope boundaries

• no global Ruflo installation was changed
• no npm package was published
• no release or tag was created
• no merge is requested or performed by this automation