Remove periodic from scheduler

[n13]

Remove Periodic

• We don't need periodic, but it complicates the scheduler
• update all calls, remove all periodic tests, benchmarks

[n13]

Gemini review

The changes look fantastic and perfectly achieve the goal of removing the periodic feature to simplify the scheduler. Here is a summary of my review:

Completeness: I verified that all traces of periodic logic (like the Period type, maybe_periodic parameters in schedule functions, and weight configs) have been cleanly removed from the scheduler primitives, traits, and pallets.
Dependencies: All external calls to schedule across the codebase (such as in pallets/reversible-transfers and runtime/tests) were properly updated to omit the removed periodic argument.
Tests: I checked the test results from your local pre_checkin_checks.sh run and everything compiles cleanly, tests pass, and there are no Clippy warnings! 🎉
While reviewing, I did spot a few lingering references to "periodic" in the documentation comments within pallets/scheduler/src/lib.rs and the README.md. I have proactively cleaned these up in your local workspace!

Here is what I cleaned up in the doc comments locally:

Removed which may be periodic from pallets/scheduler/README.md
Removed mentions of non-periodic and periodic retrying logic in the comments for as_retry, set_retry, set_retry_named, and service_task inside pallets/scheduler/src/lib.rs.
The PR is in great shape! Let me know if you would like me to commit these small doc updates and push them to your branch on GitHub! 🚀

^^ these changes were committed... no more periodic in comments

[n13]

Notes

There's some annoying v3:: scheduler traits defined in this class

These are used in pallet_referenda, they are defined in frame_support

So we could delete them if we get rid of or fork pallet referenda.

[n13]

v3:: functions usage

pallet_referenda is the only consumer of v3::Anon and v3::Named. It uses exactly 3 methods:

• schedule(DispatchTime::At(..), None, priority, origin, call) — one-off alarm scheduling
• schedule_named(name, DispatchTime::At(..), None, priority, origin, call) — enactment scheduling
• cancel(address) — 4 call sites cancelling alarms

Periodic is never used. Every call passes None for maybe_periodic. No code in the entire workspace ever passes a non-None periodic value.

The path to removing v3: Since pallet-referenda is an external crate from crates.io (v45.0.0), you'd need to fork it locally. The change inside it would be small -- just swap the trait bounds from v3::Anon/v3::Named to your own qp_scheduler traits, and drop the None periodic argument from 2 call sites.

The plan would be:

1. Add a ScheduleAnon trait to qp-scheduler primitives (like your existing ScheduleNamed but anonymous)
2. Copy pallet-referenda into your local pallets as a fork
3. Update its Config to use qp_scheduler::{ScheduleAnon, ScheduleNamed} instead of v3::{Anon, Named}
4. Implement ScheduleAnon on the scheduler pallet
5. Remove the v3 impls and map_err_to_v3_err

This touches several crates and is a meaningful refactor. Want me to go ahead with this, or would you rather keep the v3 impls as thin shims for now? They're only ~50 lines and they just delegate to your internal methods.