Add contributing guide and issue templates

Add GitHub issue templates for bug reports and feature requests tailored to the caveman persona, and add CONTRIBUTING.md describing how to propose changes to skills/caveman/SKILL.md (fork, edit, PR with before/after examples and rationale). These files help standardize contributions and make it easier for maintainers to review small, focused changes; also points contributors to ‘good first issue’ tasks.

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,25 @@
+---
+name: Bug report
+about: Caveman speak wrong or break
+labels: bug
+---
+
+**What happen**
+<!-- What caveman do wrong -->
+
+**Expected**
+<!-- What caveman should do -->
+
+**Before/after example**
+```
+Input: [your prompt]
+Got:   [what caveman said]
+Want:  [what caveman should say]
+```
+
+**Platform**
+- [ ] Claude Code
+- [ ] Codex
+- [ ] Other: ___
+
+**Version / install method**

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,17 @@
+---
+name: Feature request
+about: Make caveman better
+labels: enhancement
+---
+
+**What you want**
+<!-- New behavior, new persona, new rule -->
+
+**Before/after example**
+```
+Before: [current behavior]
+After:  [desired behavior]
+```
+
+**Why good**
+<!-- Why this help users -->

CONTRIBUTING.md

@@ -0,0 +1,18 @@
+# Contributing
+
+Improvements to the SKILL.md prompt are welcome — open a PR with before/after examples showing the change.
+
+## How
+
+1. Fork repo
+2. Edit `skills/caveman/SKILL.md`
+3. Open PR with:
+   - **Before:** what caveman say now
+   - **After:** what caveman say with change
+   - One sentence why change better
+
+Small focused change > big rewrite. Caveman like simple.
+
+## Ideas
+
+See [issues labeled `good first issue`](../../issues?q=label%3A%22good+first+issue%22) for starter tasks.