Codify 'no test counts in PR descriptions' in team standards + deep-review/craft-pr skills

Context

Raised in PreTourSurvey PR #4825 (E41 S18 /api/health/ready) review. Team consensus that PR descriptions should not include unit-test counts (e.g. 343/343 (+10)):

• They go stale immediately — that PR's description said 343/343 while the branch was actually at 355/355 after the deep-review round.
• The CI build runs the tests anyway, so the tally adds no signal — it's noise.
• Chris Smith raised it, Joe Brady agreed ("PR descriptions shouldn't have test counts in them because it's just noise"), Tim Zander confirmed.

The guidance currently lives only in a local memory/config file rather than the shared, synced team standards — so it isn't consistently applied across devs or by the tooling.

Goal

Move the rule into the shared sources so it propagates to everyone and to the PR-authoring/review tooling.

Acceptance criteria

• Team coding standards (standards/CLAUDE.md, synced into each dev's ~/.claude/CLAUDE.md) state that PR descriptions must not contain unit-test counts / pass tallies.
• The PR-authoring skill (craft-pr) is updated so generated PR descriptions omit test counts.
• The deep-review skill is updated so it neither adds nor expects a test-count line in PR descriptions (and does not raise a false "stale count" finding).
• Sync scripts run / documented so the change reaches all developers and the Antigravity-compiled skill copies (scripts/antigravity-sync.py).

Notes

• Non-blocking for PR #4825 — filed separately so it doesn't hold up S18.
• Origin: PR #4825 review thread on the stale-test-count nit.