fix: align plan templates and dependency guidance

[imarshallwidjaja]

PR: Align plan templates, dependencies, and handoff flow

Summary

Standardize plan-writing guidance across prompts and the writing-plans skill so task dependencies, file targets, and verification steps are consistent and actionable.

Changes

• Replace the writing-plans header with a full plan skeleton that matches Hive/Architect requirements (Discovery sub-sections, Non-Goals, Tasks).
• Require **Depends on** in every task and document the dependency syntax.
• Add explicit task fields: Files (Create/Modify/Test), What to do, Must NOT do, References (file:line), Verify (command + expected output).
• Align planning handoff flow to ask for Hygienic review before offering execution options.
• Update Hive/Architect prompts to require exact file targets and verification details.

Testing

• packages/hive-core: bun run test (pass)
• packages/opencode-hive: bun run test (pass; runtime e2e skip noted in output)

Notes

• This PR is documentation/prompt-only; no runtime logic changes.