refactor BWS server support methods

[tmcollins4]

Description

Refactors WalletService server-support methods out of the large server.ts file into focused helper modules.

Changelog

• Move advertisement helpers into server/advertisements.ts.
• Move auth/session/version helpers into server/auth.ts.
• Move logging helpers into server/logging.ts.
• Move Moralis helper methods into server/moralis.ts.
• Move tx note helpers into server/notes.ts.
• Move notification subscription helpers into server/notifications.ts.
• Move fiat/service config/cache helpers into server/services.ts.
• Move upgrade-check constants and logic into server/shared.ts and server/upgrade.ts.
• Keep WalletService public methods as delegating wrappers to preserve the existing API.

Testing Notes

• Ran BWS lint and production build.
• Ran the full BWS test suite.
• Ran BWC lint and test suite.

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Checklist

• I have read CONTRIBUTING.md and verified that this PR follows the guidelines and requirements outlined in it.