[httpsphl]

Sixth and last slice of the performance round. It is independent of the others. It touches deliveries.rs like #74, in different spots.

What changes

• The courier sleeps until the next job instead of waking every 500 ms.
  • Before: three queries every 500 ms under the store lock, idle or not.
  • It wakes at the earliest of: the first delivery of a bot's queue coming due, a lease ending, or an open task passing its deadline (courier_next_at).
  • The sleep is at least 250 ms, so a delivery that stays due cannot spin the courier.
  • It is at most poll_interval_ms, whose default goes from 500 ms to 10 s: it is now only the ceiling.
  • New messages and finished sends still wake it at once (notify).
• Delivers as the bot gets ready. The courier follows bot.state. When a bot can take messages again, its deliveries that never failed (attempts = 0) come due at once.
  • Before: a message to a bot that was starting or paused waited for its 5 s check.
  • Deliveries that failed keep their backoff, so a message that crashes the bot does not come straight back.
• Spec 6 and 9.1 describe it.

Not done here: the reconcile every 5 s. release_limits depends on it, and the session_id N+1 there is small.

Tests

• New test a_message_that_waited_for_the_bot_goes_as_soon_as_it_is_ready: a message sent while the bot is paused goes on resume without moving the manual clock. It fails without the change (I checked).
• Four tests waited for Idle and moved the clock 5 s to release a message. They no longer need to: the bot is Busy before it can be seen Idle. The backoff test (attempts ≥ 1) still waits for the clock, as it should.
• tests/courier.rs dropped from 8 s to 0.3 s.
• cargo fmt, clippy -D warnings, cargo test --workspace (three times) pass locally.

Manual check (real Claude)

• Restart a bot and send it a message while it starts. It goes out as soon as it shows "Available", not 5 s later.
• With every bot idle, the daemon (botloftd.exe) CPU in Task Manager stays near zero.
• Pause a bot, send it a message, then resume it: the message goes out right away.