feat: implement profile validation mechanism

Add /validate-profile slash command and automatic validation before application generation.

Implementation:
- Created src/.claude/commands/validate-profile.md with validation logic
  - Detects placeholder patterns like [Your name], [Company], etc.
  - Checks required sections: Personal Info, Summary, Work Experience
  - Allows optional sections to be empty (Projects, Certifications)
  - Provides clear pass/fail feedback with actionable guidance
- Updated src/CLAUDE.md to require validation before applications
  - Added Profile Validation section with validation process
  - Integrated validation as step 0 in workflow
  - Documented explicit skip validation option with warning
  - Added /validate-profile to Available Commands
- All 15 tasks completed and validated

Implements: add-profile-validation

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

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

src/CLAUDE.md

@@ -6,9 +6,56 @@ This directory contains the Job Application Framework (Bewerbungszauberer), desi
 
 **IMPORTANT**: When the user requests help with ANY job application task (CV, cover letter, email, or application advice), you MUST:
 
-1. **Always read `profile.md` first** - This file contains the applicant's verified personal and professional information
-2. **Use ONLY information from `profile.md`** - Never fabricate, assume, or hallucinate details about the applicant
-3. **Maintain consistency** - All generated documents must align with the information in `profile.md`
+1. **Validate the profile first** - Run `/validate-profile` to ensure `profile.md` is complete (see Profile Validation section below)
+2. **Always read `profile.md` first** - This file contains the applicant's verified personal and professional information
+3. **Use ONLY information from `profile.md`** - Never fabricate, assume, or hallucinate details about the applicant
+4. **Maintain consistency** - All generated documents must align with the information in `profile.md`
+
+## Profile Validation
+
+**CRITICAL**: Before generating any job application documents (CV, cover letter, or email), you MUST validate that `profile.md` is complete.
+
+### When to Validate
+
+Run `/validate-profile` automatically before:
+- Generating a CV/resume
+- Writing a cover letter
+- Drafting an application email
+- Creating any job application materials
+
+### Validation Process
+
+1. **Automatic validation**: When the user requests application generation, first run `/validate-profile`
+2. **Check results**:
+   - ✅ If validation passes → proceed with generation
+   - ❌ If validation fails → inform the user of incomplete sections and STOP
+3. **User action**: User must complete the profile sections flagged by validation
+4. **Re-validate**: After user updates `profile.md`, run `/validate-profile` again before proceeding
+
+### Handling Validation Failures
+
+If `/validate-profile` reports incomplete sections:
+
+1. **Do NOT generate documents** - Incomplete profiles will result in placeholder text in professional documents
+2. **Show validation results** - Display which sections need completion
+3. **Guide the user**: "Your profile has incomplete sections. Please update `profile.md` with your real information in the following areas: [list sections]. Run `/validate-profile` again when ready."
+4. **Wait for updates**: Do not proceed until validation passes
+
+### Explicit Skip Option
+
+If the user explicitly requests to skip validation with phrases like:
+- "Generate CV without validation"
+- "I know my profile is incomplete, proceed anyway"
+- "Skip validation and generate"
+
+You MAY proceed with a clear warning:
+```
+⚠️  WARNING: Proceeding without validation. Your profile may contain placeholder text.
+Generated documents might include [Your Name], [Company], or other template text.
+Please review carefully and manually replace any placeholders before sending to employers.
+```
+
+**Default behavior**: ALWAYS validate unless explicitly told to skip.
 
 ## When to Read the Profile
 
@@ -26,6 +73,11 @@ Read `profile.md` automatically when the user asks for help with:
 
 When helping with job applications, follow this workflow:
 
+### 0. Profile Validation (REQUIRED FIRST STEP)
+- Run `/validate-profile` to check `profile.md` is complete
+- If validation fails, stop and ask user to complete profile
+- If validation passes or user explicitly skips, proceed to step 1
+
 ### 1. Research & Context
 - Read the job description provided by the user
 - Extract key requirements, skills, and keywords
@@ -99,17 +151,23 @@ Adjust recommendations based on the target market if the user specifies a differ
 - Fact-check company names, contact persons, and details from job postings
 - Maintain consistency across all documents for a single application
 
+## Available Commands
+
+- `/validate-profile` - Validate that `profile.md` is complete and ready for application generation
+
 ## Example Usage
 
 **User**: "Help me apply for this software engineering position at TechCorp [paste job description]"
 
 **Claude Code should**:
-1. Read `profile.md` to load applicant information
-2. Analyze the job description for requirements and culture
-3. Identify matching experiences and skills from the profile
-4. Ask clarifying questions: "Would you like me to create a CV, cover letter, or both?"
-5. Generate tailored documents using only information from `profile.md`
-6. Ensure all documents are consistent and factually accurate
+1. Run `/validate-profile` to check profile completeness
+2. If validation fails: inform user of incomplete sections and stop
+3. If validation passes: Read `profile.md` to load applicant information
+4. Analyze the job description for requirements and culture
+5. Identify matching experiences and skills from the profile
+6. Ask clarifying questions: "Would you like me to create a CV, cover letter, or both?"
+7. Generate tailored documents using only information from `profile.md`
+8. Ensure all documents are consistent and factually accurate
 
 ## Updating the Profile