fix(#647): the guard counted its own in-flight run

[TortoiseWolfe]

The finding is in #647. This is the fix.

runConsumedQuota treats any non-completed run as having spent quota — right in general,
since an in-flight run really may be testing right now. But the guard's own run is
in_progress while its budget job executes, and nothing excluded it.

So it always counted itself, and the daily cap of 10 behaved as 9: at limit - 1 it
adds itself, hits the limit exactly, and refuses.

Observed, with nothing else running in between

time	reading	source
15:59Z	9 / 10 — OK	manual --dry-run
16:00Z	10 / 10 — DAY_EXCEEDED	the budget job on the run created at 16:00Z
16:20Z	9 / 10 — OK	manual, after that run finished all-skipped

Job 93123780234 on run 31265873093 logged the 10/10 directly.

What it cost

#644 merged with no E2E behind it. The merge order was changed specifically so each PR
would land covered once the meter was honest (#640/#645). The cycle window was fixed and the
day window read 9/10 OK immediately before the merge — then the run blocked itself. The one
thing the ordering existed to guarantee is the thing that did not happen.

The fix

Thread GITHUB_RUN_ID through countRuns, skip that run in both windows.

Compare as strings. GITHUB_RUN_ID arrives as a string, the API returns id as a
number; a strict === between them silently excludes nothing and restores the bug. There is
a test for exactly that, and tightening the comparison fails two.

Absent GITHUB_RUN_ID — local invocation, --dry-run — nothing is excluded. That is why
the manual readings above were right all along and CI's was not.

Verification

• 4 new tests (32 in the file, 177/177 in test:scripts), each mutation-proven:
  removing the exclusion fails 3, tightening to === fails 2.
• One test reproduces the whole defect end to end — 9 other runs plus itself = 10 = refuse.
• My first fixture omitted total_count and all 4 tests failed on listRuns before reaching
  the exclusion. Fixed the fixture, not the code.

Third defect in this counter, all the same shape

Counting something that is not evidence of quota spent:

• Quota circuit breaker counts its own blocked runs, so it ratchets itself shut #640 — counted runs the breaker itself had blocked, and a deleted project's runs
  against the live one
• E2E watchdog reports a quota-blocked run as covered, when zero tests ran #639 — the watchdog called a blocked run "covered"
• this — counts itself

Closes #647