feat: raise shared memory defaults on the 3.9.x chart line

[jarvis9443]

Raise the non-evictable shared-memory defaults on the 3.9.x chart line, mirroring #310 (which does the same for the 3.10.x line on `main`).

These zones drop data when full rather than evicting, so their defaults are sized for typical deployments instead of the old minimal values:

• `prometheus-metrics` 15m → 256m
• `tracing_buffer` 10m → 32m
• `api-calls-for-portal` added at 64m (Developer Portal API-usage counters)
• `customLuaSharedDicts` seeds `kubernetes` / `nacos` / `consul` service discovery at 64m each

Any of these can still be overridden through the chart values. Gateway chart bumped 3.9.2 → 3.9.3.

`nacos-stream` does not exist on the 3.9.x line, so it is left untouched (unlike #310).

Fixes api7/api7-ee-3-gateway#1869

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