chore(guides): platform-accuracy fixes — dead options + run.mount drift

[krls2020]

Platform-accuracy fixes across 5 guides, each verified against the live Zerops import / zerops.yml JSON schemas. Surfaced by a ZCP knowledge investigation (a Typesense query was being read as "not a managed service").

• choose-search — the lead named only 3 of the 4 managed search engines (Typesense was missing from the headline, relegated to the matrix). Now names all four (Meilisearch / Elasticsearch / Typesense / Qdrant); matrix surfaces each engine's disqualifying constraint inline.
• choose-cache — removed the KeyDB matrix row. KeyDB is no longer offerable (absent from the live import schema; only valkey:ha@7.2 / valkey:single@7.2 exist for caching). Presenting it as a pickable Choice cell surfaced a dead option an agent would try to import and fail. Deprecation prose in the lead is kept.
• production-checklist — "Redis/Valkey" → "Valkey" in the sessions line + table. Redis is not an offerable managed type on Zerops (redis → valkey). Framework-driver mentions (Laravel/Django/Express "Redis driver/backend/store") left intact — those name the redis-protocol driver Valkey serves.
• scaling — "Managed cache (KeyDB/Valkey)" → "(Valkey)", same dead-option reason.
• deployment-lifecycle — corrected a fabricated zerops.yml run.mount. The zerops.yml schema has no mount field; the only shared-storage mount mechanism is the service-level mount: in import.yaml.

Generated from ZCP via sync push guides.