docs: update API paths to /v1/memories/* prefix

[ethanj]

Summary

• Core now serves memory routes under the `/v1` version prefix; rewrite all docs references from `/memories/` to `/v1/memories/`.
• Covers quickstart, platform pages (composition, observability, scope), and the full HTTP API reference (agents, audit, config, consolidate-decay-cap, conventions, ingest, lessons, list-get-delete, search).

Test plan

• `npm run build` (or equivalent) to confirm Docusaurus builds without broken internal links
• Spot-check a few rendered pages locally to confirm curl examples display correctly
• `grep -r "/memories/" docs/` returns only the `/v1/memories/` form

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