feat: 100 skills milestone — 7 new skills + quality improvements across all 93

New skills added:
- teaching-lesson-plan: structured lesson plans for any subject/audience/setting
- seo-content-brief: complete SEO briefs with intent, competitor gaps, and outline
- media-pitch: story-first journalist pitches with angle development framework
- change-management-plan: stakeholder analysis, comms strategy, adoption metrics
- workshop-facilitation-guide: activity instructions, decision protocols, facilitator moves
- sales-forecasting-model: pipeline model, scenario analysis, assumption log
- tax-planning-checklist: year-end tax planning across income, pension, CGT, reliefs

Quality improvements across all 93 existing skills:
- Standardised description format: "Verb the thing. Use when X. Produces Y."
- Added Required Inputs section to all skills missing it (prompts for missing info)
- Added Quality Checks section to all skills missing it (specific, not generic)
- Fixed broken multiline YAML descriptions
- Removed non-standard frontmatter keys (tool_integration, metadata blocks)

README updated to v6.0.0 with 100-skill count, new skill tables, and article series

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

skills/executive-update/SKILL.md

@@ -1,13 +1,20 @@
 ---
 name: executive-update
-description: Transform detailed product updates into concise executive briefings
-tool_integration: Slack, Microsoft Teams
+description: "Transform detailed product updates into concise executive briefings. Use when asked to write an executive update, leadership update, product update for the exec team, or a C-suite product briefing. Produces a structured 250-word briefing with headline, key metrics, progress, risks, decisions needed, and next steps."
 ---
+
 # Executive Update Skill
 
-## Purpose
 Produce a stakeholder update that busy executives will actually read — structured around what they care about: decisions, risks, and numbers.
 
+## Required Inputs
+
+Ask the user for these if not provided:
+- **Product update or notes** (raw input to transform — even bullet points work)
+- **Audience** (CEO, board, specific exec, or general leadership)
+- **Period** (this week / sprint / month / quarter)
+- **Key metrics** (what numbers matter to this audience)
+
 ## Executive Communication Principles
 - Lead with the headline, not the context
 - Every update should answer: "So what does this mean for the business?"
@@ -20,8 +27,9 @@ Produce a stakeholder update that busy executives will actually read — structu
 3. Write in reverse pyramid style — most important first
 4. Limit to 250 words maximum for the main body
 5. Add a "Decisions Needed" section with clear options and your recommendation
+6. **Validate** — Confirm every decision needed has a specific option and recommendation (not just "TBD"), and every risk has a mitigation or watch plan
 
-## Output Format
+## Output Structure
 
 ### Product Update — [Date / Sprint / Month]
 **Headline:** [One sentence on the most important thing]
@@ -42,3 +50,11 @@ Produce a stakeholder update that busy executives will actually read — structu
 
 **What's Next:**
 [2-3 bullets on next period priorities]
+
+## Quality Checks
+
+- [ ] Whole update is under 250 words (if not, cut ruthlessly)
+- [ ] Every metric includes a comparison point (vs. target or last period)
+- [ ] Every risk has a mitigation or watch action
+- [ ] Every decision needed has at least two options and a recommendation
+- [ ] Written for a CFO or CEO — no jargon, all outcomes