feat(writing-skills): refactor skill to gold standard architecture

skills/writing-skills/references/tier-1-simple/README.md

@@ -0,0 +1,75 @@
+---
+description: When to use Tier 1 (Simple) skill architecture.
+metadata:
+  tags: [tier-1, simple, single-file]
+---
+
+# Tier 1: Simple Skills
+
+Single-file skills for focused, specific purposes.
+
+## When to Use
+
+- **Single concept**: One technique, one pattern, one reference
+- **Under 200 lines**: Can fit comfortably in one file
+- **No complex decision logic**: User knows exactly what they need
+- **Frequently loaded**: Needs minimal token footprint
+
+## Structure
+
+```
+my-skill/
+└── SKILL.md          # Everything in one file
+```
+
+## Example
+
+```yaml
+---
+name: flatten-with-flags
+description: Use when simplifying deeply nested conditionals.
+metadata:
+  category: pattern
+  triggers: nested if, complex conditionals, early return
+---
+
+# Flatten with Flags
+
+## When to Use
+- Code has 3+ levels of nesting
+- Conditions are hard to follow
+
+## The Pattern
+Replace nested conditions with early returns and flag variables.
+
+## Before
+```javascript
+function process(data) {
+  if (data) {
+    if (data.valid) {
+      if (data.ready) {
+        return doWork(data);
+      }
+    }
+  }
+  return null;
+}
+```
+
+## After
+```javascript
+function process(data) {
+  if (!data) return null;
+  if (!data.valid) return null;
+  if (!data.ready) return null;
+  return doWork(data);
+}
+```
+```
+
+## Checklist
+
+- [ ] Fits in <200 lines
+- [ ] Single focused purpose
+- [ ] No need for `references/` directory
+- [ ] Description uses "Use when..." pattern