docs: require supported Hermes installer

[phernandez]

Why

• [BUG] Hermes install docs use unsupported --path and fail on latest stable basic-memory#1280 identified that the published Hermes install command uses a
  nonexistent --path option.
• The maintained Basic Memory plugin requires manifest-v2 installer support, so the docs should
  state that compatibility floor instead of presenting older Hermes releases as supported.

Addresses basicmachines-co/basic-memory#1280 and accompanies basicmachines-co/basic-memory#1303.

What Changed

• Replaced the unsupported command on the Hermes integration and announcement pages with Hermes's
  monorepo-subdirectory identifier.
• Documented that managed installation requires the upstream manifest-v2 installer fix and that
  Hermes Agent v0.20.5 and earlier are unsupported.

Implementation Details

• The public docs link directly to plugins install caps manifest_version at 1 while the runtime loader supports 2 NousResearch/hermes-agent#85893 for the host-side prerequisite.
• No manual clone or deprecated pointer-repository fallback is advertised.

Testing

Automated

• npm run build: passed.
• git diff --check: passed.
• Confirmed no --path integrations/hermes command remains under content/.

Manual

• Reviewed both rendered-content sources for consistent commands and version language.

Risks / Follow-ups

• No currently released Hermes version includes the required installer fix; the pages now say so
  explicitly rather than promising a broken installation path.
• Update the minimum version once upstream #85893 ships in a tagged release.