feat(pi): add skills and improve AGENTS.md reading guidelines

- Add 'create-skill' skill for scaffolding new skill directories
- Add 'planning' skill for structured implementation workflows
- Add search-then-read pattern guidance to AGENTS.md

modules/home/programs/terminal/pi/config/skills/planning/SKILL.md

@@ -0,0 +1,71 @@
+---
+name: planning
+description: 'Create a structured plan before implementing broad or non-trivial changes. Use when user requests a new feature spanning multiple areas, significant refactoring, or explicitly asks to "plan this out". Produces a plan document in _scratch/, waits for user approval, then tracks progress as tasks are completed.'
+---
+
+# Planning Workflow Skill
+
+## When to Use
+
+Trigger this workflow when:
+- A user requests a **broad or non-trivial change** (e.g. new feature spanning frontend/backend, significant refactoring)
+- A user says things like "plan this out", "create a plan", or "do this properly"
+
+Don't trigger for routine multi-file changes like renames, simple bug fixes, or mechanical refactors.
+
+## Rules
+
+### 1. Always Start with a Plan
+
+**Before touching any code**, create a markdown plan in `_scratch/plan-[short-name].md` with:
+- A clear title and status
+- Clarifications section (if any unknowns)
+- Phased tasks as checkboxes (`- [ ]`)
+
+### 2. Ask Clarifying Questions First
+
+When a requirement is **ambiguous or has multiple valid interpretations**:
+- List your interpretations
+- Ask the user to confirm
+- Document answers in the plan's "Clarifications" section
+
+### 3. Wait for User Approval
+
+Present the plan and wait for the user to confirm before implementing. If the user requests changes, update the plan first.
+
+### 4. Update the Plan as You Work
+
+- Change `- [ ]` to `- [x]` for completed items
+- Note any deviations from the original plan
+- If you discover new tasks, add them with a note explaining why
+
+### 5. Plan Document Format
+
+```markdown
+# Plan: [Feature Name]
+
+> **Status**: ⏳ In Progress | ✅ Complete | ❌ Blocked
+
+## Clarifications
+
+- ~~Question?~~ **Answer**
+
+## Tasks
+
+### Phase 1: [Name]
+- [ ] Task 1
+- [ ] Task 2
+
+### Phase 2: [Name]
+- [ ] Task 3
+
+## Rollback Plan (if destructive/irreversible)
+[How to undo if needed]
+```
+
+## Anti-Patterns
+
+- ❌ Coding before the user approves the plan
+- ❌ Making assumptions about ambiguous requirements
+- ❌ Plans that are too vague ("update code")
+- ❌ Forgetting to update the plan as you work