Add CLAUDE.md reading instructions to subagent prompts

[Jah-yee]

Summary

Subagent prompts should include explicit instructions to read the project's CLAUDE.md file to ensure they follow project-specific conventions and coding standards.

This addresses issue #793 where subagents were not respecting project conventions defined in CLAUDE.md.

Changes

Added a "Project Conventions" section at the beginning of:

• implementer-prompt.md - Instructs implementer agents to read CLAUDE.md before starting
• spec-reviewer-prompt.md - Instructs spec reviewer agents to read CLAUDE.md as their quality benchmark
• requesting-code-review/code-reviewer.md - Instructs code reviewer agents to read CLAUDE.md for style preferences

Testing

The changes are template updates only. The new instructions will take effect when new subagents are dispatched using these templates.

[arittr]

Hey @Jah-yee - heads up, we just opened #899 which overlaps with this. Same goal (get subagents to read CLAUDE.md), but we went with a minimal one-liner approach after RED/GREEN testing across a bunch of scenarios. Closing this one in favor of #899 — thanks for flagging the issue originally!