chore(gkg): bump image to v0.71.0 (stg+prd) + enable system_notes in prd (chart 1.1.0)

Two changes, both landing in orbit-prd on this rollout:

1. Image bump 0.70.1 → 0.71.0 for both orbit-stg and orbit-prd.
2. Enable system_notes in orbit-prd, which also bumps the prd chart 1.0.0 → 1.1.0 (the feature-flag passthrough was only added in chart 1.1.0, so the flag is a no-op without it). stg already runs chart 1.1.0 with system_notes: true.

Release: https://gitlab.com/gitlab-org/orbit/knowledge-graph/-/releases/v0.71.0

system_notes requires image.tag >= 0.70.0 (satisfied by 0.71.0) and turns on SystemNotes entity/edge ingestion via the sdlc module — a new write path in prod, so worth watching indexing load + the schema migration after ArgoCD syncs.

Files changed

• services/gkg/env/orbit-stg/values.yaml — image.tag 0.70.1 → 0.71.0
• services/gkg/env/orbit-prd/values.yaml — image.tag 0.70.1 → 0.71.0; add features.system_notes: true
• services/gkg/env/orbit-prd/app.yaml — chart 1.0.0 → 1.1.0