#14073: [wip]support OpenViking Memory Plugin

<!-- greptile_comment --> <h2>Greptile Overview</h2> <h3>Greptile Summary</h3> This PR adds a new `memory-openviking` extension plugin implementing long-term memory via an OpenViking HTTP service, including tools (`memory_store`, `memory_recall`, `memory_forget`), optional auto-recall/auto-capture hooks, docs/runbook entries, and a helper E2E script. Key integration points are via the plugin SDK hook system (`before_agent_start` for recall context injection and `agent_end` for capture), matching the existing `memory-lancedb` pattern, plus a new package under `extensions/memory-openviking` and corresponding lockfile/docs updates. <h3>Confidence Score: 3/5</h3> - This PR is close to mergeable but has a couple of concrete issues that can break usage and safety of the provided E2E script. - Core plugin wiring and hook usage aligns with existing patterns, but (1) the E2E script uses unscoped `pkill -f` which can terminate unrelated processes, and (2) the config env fallback for the API key is inconsistent with the tests/examples, leading to auth failures when users rely on `MEMORY_OPENVIKING_API_KEY` alone. - scripts/openviking-e2e.sh, extensions/memory-openviking/config.ts <!-- greptile_other_comments_section --> _{(2/5) Greptile learns from your feedback when you react with thumbs up/down!} <!-- /greptile_comment -->