fix(writing-skills): replace count anchors with standard-based language

[citizen204]

Summary

Fixes #1487, filed by @obra.

Replaces the '3+ combined pressures' count targets with qualitative standards at all 5 sites across \SKILL.md\ and \ esting-skills-with-subagents.md.

The problem

The count anchor was doing gating work that the actual standard should carry. As demonstrated in the issue, agents hit the count and stop — leaving material unexamined — rather than continuing until the standard is met. A scenario with two strong, well-aligned pressures can trigger the target rationalization more reliably than four weak unaligned ones.

Changes

*\skills/writing-skills/SKILL.md* (1 site)

• Line 601: Replaced (3+ combined pressures for discipline skills)\ with standard-based language: scenarios that reliably trigger the rationalizations you want to prevent

*\skills/writing-skills/testing-skills-with-subagents.md* (4 sites)

• Line 51: Removed count anchor from the RED phase checklist item
• Line 140: Replaced \Best tests combine 3+ pressures\ with the qualitative diagnostic: does an agent without the skill consistently take the rationalization path?
• Line 313: Removed count anchor from the final testing checklist
• Line 344: Replaced the fix prescription \Combine 3+ pressures\ with the actual standard

The replacement standard (from the issue)

Pressure scenarios should reliably trigger the rationalizations you want to prevent. The diagnostic for whether a scenario is good enough: does an agent without the skill, run on this scenario, consistently take the rationalization path you're trying to close?