feat: v3.0.0 architecture overhaul

- Rename marketplace to lm-claude-plugins
- Move MCP servers to root with symlinks
- Add 6 PR tools to Gitea MCP (list_pull_requests, get_pull_request,
  get_pr_diff, get_pr_comments, create_pr_review, add_pr_comment)
- Add clarity-assist plugin (prompt optimization with ND accommodations)
- Add git-flow plugin (workflow automation)
- Add pr-review plugin (multi-agent review with confidence scoring)
- Centralize configuration docs
- Update all documentation for v3.0.0

BREAKING CHANGE: MCP server paths changed, marketplace renamed

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

plugins/git-flow/commands/branch-start.md

@@ -0,0 +1,96 @@
+# /branch-start - Start New Branch
+
+## Purpose
+
+Create a new feature/fix/chore branch with consistent naming conventions.
+
+## Usage
+
+```
+/branch-start [description]
+```
+
+## Behavior
+
+### Step 1: Determine Branch Type
+
+```
+What type of change is this?
+1. feat - New feature
+2. fix - Bug fix
+3. chore - Maintenance task
+4. docs - Documentation
+5. refactor - Code refactoring
+```
+
+### Step 2: Get Description
+
+If not provided, ask:
+
+```
+Brief description (2-4 words):
+> add user authentication
+```
+
+### Step 3: Generate Branch Name
+
+Convert to kebab-case:
+- `feat/add-user-authentication`
+- `fix/login-timeout-error`
+- `chore/update-dependencies`
+
+### Step 4: Create Branch
+
+```bash
+# Ensure base branch is up-to-date
+git checkout <base-branch>
+git pull origin <base-branch>
+
+# Create and switch to new branch
+git checkout -b <new-branch>
+```
+
+### Step 5: Confirm
+
+```
+Created branch: feat/add-user-authentication
+Based on: development (abc1234)
+
+Ready to start coding!
+```
+
+## Environment Variables
+
+| Variable | Default | Description |
+|----------|---------|-------------|
+| `GIT_DEFAULT_BASE` | `development` | Branch to create from |
+| `GIT_BRANCH_PREFIX` | `true` | Use type/ prefix |
+
+## Naming Rules
+
+- Lowercase only
+- Hyphens for spaces
+- No special characters
+- Max 50 characters
+
+## Validation
+
+```
+Branch name validation:
+✓ Lowercase
+✓ Valid prefix (feat/)
+✓ Descriptive (3+ words recommended)
+✗ Too long (52 chars, max 50)
+
+Suggested: feat/add-user-auth
+Use this instead? (y/n)
+```
+
+## Output
+
+On success:
+```
+Branch: feat/add-user-authentication
+Base: development @ abc1234
+Status: Ready for development
+```