fix(chart): set numeric security user

[casey-brooks]

Summary

• Adds numeric default runAsUser: 100 and runAsGroup: 101 alongside runAsNonRoot: true in the chart security context.
• Leaves umbrella/provisioning unchanged; this is chart-owned.

Fixes #38

Validation

• buf generate buf.build/agynio/api --path agynio/api/threads/v1 --path agynio/api/notifications/v1 --path agynio/api/identity/v1 --path agynio/api/metering/v1 --path agynio/api/agents/v1 --path agynio/api/authorization/v1
• go test ./... — 3 passed, 0 failed, 0 skipped
• helm dependency build charts/threads
• helm lint charts/threads — 1 chart linted, 0 failed
• helm template threads charts/threads — rendered runAsNonRoot: true, runAsUser: 100, and runAsGroup: 101
• gofmt -w $(git ls-files '*.go')
• git diff --check

Release note

Chart release/version bump should happen after merge only.

[casey-brooks]

Summary

• Adds numeric default runAsUser: 100 and runAsGroup: 101 alongside runAsNonRoot: true in the chart security context.
• Leaves umbrella/provisioning unchanged; this is chart-owned.

Fixes #38

Validation

• buf generate buf.build/agynio/api --path agynio/api/threads/v1 --path agynio/api/notifications/v1 --path agynio/api/identity/v1 --path agynio/api/metering/v1 --path agynio/api/agents/v1 --path agynio/api/authorization/v1
• go test ./... — 3 passed, 0 failed, 0 skipped
• helm dependency build charts/threads
• helm lint charts/threads — 1 chart linted, 0 failed
• helm template threads charts/threads — rendered runAsNonRoot: true, runAsUser: 100, and runAsGroup: 101
• gofmt -w $(git ls-files '*.go')
• git diff --check

Release note

Chart release/version bump should happen after merge only.

[noa-lucent]

Review complete. The chart defaults now include numeric runAsUser/runAsGroup alongside runAsNonRoot, matching the issue's requested security context and avoiding the named-image-user startup failure. No blocking comments.