feat(skills): Add consensus-voting skill for multi-agent decisions (#1620)

* feat(skills): Add consensus-voting skill for multi-agent decisions

Add new skill for weighted multi-agent voting:
- Invokes multiple agents in parallel for critical decisions
- Weighted voting based on domain expertise
- Auto-triggers for security, auth, data-handling
- Three modes: supermajority (66%), simple-majority (50%), unanimous
- Integrates with debate-workflow and n-version-workflow

Part of Issue #1611 Enhancement 10

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

* fix(skill): Remove unimplemented adaptive calibration from consensus-voting

Removes references to "adaptive" weight calibration mode that was documented
but never implemented, violating Zero-BS philosophy (no stubs/placeholders).

Keeps only the implemented "static" calibration mode.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

---------

Co-authored-by: Ubuntu <azureuser@amplihack2.yb0a3bvkdghunmsjr4s3fnfhra.phxx.internal.cloudapp.net>
Co-authored-by: Claude <noreply@anthropic.com>

Author: 3 people

.claude/skills/consensus-voting/README.md

@@ -0,0 +1,120 @@
+# Consensus Voting Skill
+
+Multi-agent consensus voting with domain-weighted expertise for critical decisions.
+
+## Quick Start
+
+### Auto-Activation
+
+The skill automatically activates when working with:
+
+- Security implementations (authentication, authorization)
+- Encryption and cryptographic code
+- Sensitive data handling (PII, credentials)
+- Permission and access control changes
+
+### Explicit Trigger
+
+```bash
+/amplihack:consensus-vote "Should we use JWT or session cookies for auth?"
+```
+
+Or invoke programmatically:
+
+```python
+Skill(skill="consensus-voting")
+```
+
+## How It Works
+
+1. **Domain Detection** - Analyzes change to determine expertise area
+2. **Agent Selection** - Selects relevant agents with domain-specific weights
+3. **Voting** - Each agent votes with confidence level
+4. **Weighted Calculation** - Applies expertise weights to votes
+5. **Threshold Check** - Validates against voting mode (supermajority default)
+6. **Result Report** - Documents decision with reasoning and dissent
+
+## Key Concept: Weighted Voting
+
+Unlike simple majority voting, this skill weights votes by domain expertise:
+
+| Domain    | Top Expert (3x) | Strong (2x)       | Standard (1x)    |
+| --------- | --------------- | ----------------- | ---------------- |
+| Security  | security        | architect         | reviewer, tester |
+| Auth      | security        | architect         | reviewer, tester |
+| Data      | security        | architect         | reviewer, tester |
+| Algorithm | optimizer       | architect, tester | reviewer         |
+
+## When to Use vs Alternatives
+
+| Scenario               | Use This         | Alternative        |
+| ---------------------- | ---------------- | ------------------ |
+| Binary security choice | consensus-voting | -                  |
+| Complex trade-offs     | -                | debate-workflow    |
+| Code generation        | -                | n-version-workflow |
+| Design exploration     | -                | debate-workflow    |
+| Risk validation        | consensus-voting | -                  |
+
+## Voting Modes
+
+- **supermajority** (66%+) - Default for security, requires strong consensus
+- **simple-majority** (50%+) - Faster decisions, lower bar
+- **unanimous** (100%) - Highest bar, all must agree
+
+## Example Output
+
+```markdown
+## Consensus Voting Result
+
+**Decision:** Use argon2id for password hashing
+**Domain:** AUTH
+**Threshold:** Supermajority (66%+)
+**Result:** PASSED (68.2%)
+
+### Vote Summary
+
+| Agent     | Weight | Vote     | Confidence |
+| --------- | ------ | -------- | ---------- |
+| security  | 2.5    | argon2id | HIGH       |
+| architect | 2.0    | argon2id | MEDIUM     |
+| reviewer  | 1.5    | bcrypt   | HIGH       |
+| tester    | 1.5    | argon2id | MEDIUM     |
+
+### Key Reasoning
+
+- **security (2.5):** "OWASP current recommendation, memory-hard"
+
+### Dissenting View
+
+- **reviewer (1.5):** "bcrypt more battle-tested in production"
+```
+
+## Integration
+
+### With Debate Workflow
+
+When voting fails to reach consensus, escalate:
+
+```
+No consensus (52.1%) → Invoke debate-workflow
+```
+
+### With N-Version Workflow
+
+Use voting to select between N-version implementations:
+
+```
+N-version → 3 implementations → Consensus vote → Winner
+```
+
+## Files
+
+- `SKILL.md` - Full skill definition with execution process
+- `README.md` - This documentation (usage guide)
+
+## Philosophy Alignment
+
+- **Evidence-Based:** All votes require reasoning
+- **Expertise-Weighted:** Domain knowledge matters
+- **Transparent:** Dissent documented, not hidden
+- **Appropriate Rigor:** Auto-triggers for high-risk domains