Fixes #92536.

This completes the Dreaming memory sidecar path when a trusted selected memory plugin, such as memory-lancedb or memory-lancedb-pro, has Dreaming enabled but a restrictive plugins.allow list omits memory-core. The fix should treat memory-core as a narrow runtime dependency of that selected memory slot plugin, not as a general allowlist bypass.

Implementation notes:

• Keep plugins.deny, entries.memory-core.enabled = false, and plugins.slots.memory = "none" fail-closed.
• Only authorize memory-core when Dreaming resolves enabled from the selected memory slot plugin config and the selected slot plugin itself is trusted/allowed and memory-kind.
• Cover full loader, loadModules: false snapshot loading, CLI metadata registry loading, and gateway startup plugin planning.
• Add regression coverage for memory-lancedb/memory-lancedb-pro-style config where plugins.allow includes the selected memory plugin but omits memory-core, plus disabled/missing-slot negative cases.

Credit: reported by @resYuto in #92536, with additional reproduction detail from @wangsheng520520 and @icophy. This builds on the earlier loader-sidecar work by @pradeep7127 in #65411.

Clownfish 🐠 replacement reef notes:

• Cluster: gitcrawl-426-autonomous-terminal-gap
• Source PRs: fix(plugins): exempt dreaming engine from memory slot fast-path in loader #65411
• Credit: Credit [Bug]: Dreaming sweeps not working if use Dreaming-compatible memory plugin #92536 reporter @resYuto for the restrictive-allowlist Dreaming reproduction.; Mention the additional operational data points from @wangsheng520520 and @icophy on [Bug]: Dreaming sweeps not working if use Dreaming-compatible memory plugin #92536 in the PR body as validation context.; Credit @pradeep7127 and fix(plugins): exempt dreaming engine from memory slot fast-path in loader #65411 for the earlier loader-sidecar groundwork that this fix narrows and completes.
• Validation: pnpm -s vitest run src/plugins/loader.test.ts src/plugins/channel-plugin-ids.test.ts; pnpm check:changed

fish notes: model gpt-5.5, reasoning medium; reviewed against 9d0cd3a.