The Koordinator's brief no longer loses what happened between two commands

With each command, the Koordinator hears what happened on the canvas since the previous one. Each brief remembered the clock time it was read at. The next brief then read everything later than that. Anything logged in the same millisecond, or after the machine's clock stepped back, fell into the gap. On CI, the test caught this now and then.

What happened on CI (run 39601318777)

A card was created and an agent asked a question between two commands. The second brief lists the new card, but its "What happened since" section is missing:

Now: Wed 2026-10-21 12:40.

The owner said (speech recognition, may contain errors): "und die andere auch"
…
Cards on the canvas now:
K1 [planned] "Export"
K2 [planned] "Login"
  ← no "What happened on the canvas since the owner's last command:"

The same scenario with the clock pinned to one millisecond

Before
The owner said: "und?"
…
Cards on the canvas now:
K1 [planned] "Export"
  ← the agent's question is missing

The new test fails.

After
What happened on the canvas since the owner's last command:
- … K1 "Export": the agent asked: CSV oder Excel?

The owner said: "und?"

Now passes. A clock that steps back 50 ms loses nothing either, and nothing comes twice.

The fix

Every entry in the history gets a number that keeps counting up. Each brief now also stores the newest number it read, and the next brief adds everything numbered higher, whatever its clock time.

Checks

50 / 50
runs of the Koordinator memory tests in a row, all green
1356 / 0
tests passed / failed in the full suite; typecheck clean