Allow fresh 2.x installs without legacy 1.x tables or drain overhead

[rmcdaniel]

Independently verified problem

WorkflowServiceProvider::boot() unconditionally loads src/migrations, including all six 2022_01_01_* migrations. A fresh 2.x install therefore creates workflows, workflow_logs, workflow_signals, workflow_timers, workflow_exceptions, and workflow_relationships, even if the application only uses v2.

The queue Looping listener also always calls the legacy Watchdog::wake(). The watchdog checks whether the legacy table exists, but the default fresh migration creates it.

This is avoidable installation/operation overhead, not evidence of a failed v2 workflow or a data-integrity defect. Retained v1 code supports existing applications draining old work; deleting it indiscriminately would break that adoption path.

Intended outcome

Provide an explicit, documented v2-only installation path, and review whether fresh installs can select it automatically without changing existing applications' behavior. Keep legacy migration/drain support available for real 1.x upgrades. Do not automatically drop any existing tables or history.

Acceptance

• Fresh v2-only migrations create the required v2 schema without the six legacy tables.
• v2-only queue execution does not poll/schedule legacy watchdog work.
• Existing 1.x installations can still drain old workflows while starting v2 work; reopening an existing application must not silently disable recovery.
• Published migrations, migration ledger identity, rollback behavior, custom storage connections, and cached configuration have focused regression coverage.
• Waterline embedded installation and Server consumption are checked against the chosen mode.
• Document the upgrade-safe switch and publish a semver-appropriate release with a clean-install check against published artifacts.

Priority

Accepted product cleanup, after active reliability/recovery work and already accepted user-reported defects. Do not turn this into removal of supported upgrade functionality or a prerequisite for unrelated Cloud recovery qualification.