feat(memory): add gemini-embedding-2-preview support (#42501)

Merged via squash.

Prepared head SHA: c57b1f8ba2
Co-authored-by: BillChirico <13951316+BillChirico@users.noreply.github.com>
Co-authored-by: gumadeiras <5599352+gumadeiras@users.noreply.github.com>
Reviewed-by: @gumadeiras

CHANGELOG.md

@@ -12,6 +12,7 @@ Docs: https://docs.openclaw.ai
 - Exec/child commands: mark child command environments with `OPENCLAW_CLI` so subprocesses can detect when they were launched from the OpenClaw CLI. (#41411) Thanks @vincentkoc.
 - iOS/Home canvas: add a bundled welcome screen with a live agent overview that refreshes on connect, reconnect, and foreground return, and move the compact connection pill off the top-left canvas overlay. (#42456) Thanks @ngutman.
 - iOS/Home canvas: replace floating controls with a docked toolbar, make the bundled home scaffold adapt to smaller phones, and open chat in the resolved main session instead of a synthetic `ios` session. (#42456) Thanks @ngutman.
+- Memory/Gemini: add `gemini-embedding-2-preview` memory-search support with configurable output dimensions and automatic reindexing when the configured dimensions change. (#42501) thanks @BillChirico.
 - Discord/auto threads: add `autoArchiveDuration` channel config for auto-created threads so Discord thread archiving can stay at 1 hour, 1 day, 3 days, or 1 week instead of always using the 1-hour default. (#35065) Thanks @davidguttman.
 - OpenCode/onboarding: add new OpenCode Go provider, treat Zen and Go as one OpenCode setup in the wizard/docs while keeping the runtime providers split, store one shared OpenCode key for both profiles, and stop overriding the built-in `opencode-go` catalog routing. (#42313) Thanks @ImLukeF and @vincentkoc.
 - macOS/chat UI: add a chat model picker, persist explicit thinking-level selections across relaunch, and harden provider-aware session model sync for the shared chat composer. (#42314) Thanks @ImLukeF.