feat(skill): add Phase 0.5 for .understandignore setup and review pause

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

understand-anything-plugin/skills/understand/SKILL.md

@@ -77,6 +77,37 @@ Determine whether to run a full analysis or incremental update.
 
 ---
 
+## Phase 0.5 — Ignore Configuration
+
+Set up and verify the `.understandignore` file before scanning.
+
+1. Check if `$PROJECT_ROOT/.understand-anything/.understandignore` exists.
+2. **If it does NOT exist**, generate a starter file:
+   - Run the following Node.js one-liner in `$PROJECT_ROOT`:
+     ```bash
+     node -e "
+     const fs = require('fs');
+     const path = require('path');
+     const root = process.cwd();
+     const dirs = ['__tests__','test','tests','fixtures','testdata','docs','examples','scripts','migrations','.storybook'];
+     const header = '# .understandignore — patterns for files/dirs to exclude from analysis\n# Syntax: same as .gitignore (globs, # comments, ! negation, trailing / for dirs)\n# Lines below are suggestions — uncomment to activate.\n# Use ! prefix to force-include something excluded by defaults.\n#\n# Built-in defaults (always excluded unless negated):\n#   node_modules/, .git/, dist/, build/, bin/, obj/, *.lock, *.min.js, etc.\n#\n';
+     let body = '';
+     const found = dirs.filter(d => fs.existsSync(path.join(root, d)));
+     if (found.length) { body += '# --- Detected directories (uncomment to exclude) ---\n\n' + found.map(d => '# ' + d + '/').join('\n') + '\n\n'; }
+     body += '# --- Test file patterns (uncomment to exclude) ---\n\n# *.test.*\n# *.spec.*\n# *.snap\n';
+     fs.writeFileSync(path.join(root, '.understand-anything', '.understandignore'), header + body);
+     "
+     ```
+   - Report to the user:
+     > Generated `.understand-anything/.understandignore` with suggested exclusions based on your project structure. Please review it and uncomment any patterns you'd like to exclude from analysis. When ready, confirm to continue.
+   - **Wait for user confirmation before proceeding.**
+3. **If it already exists**, report:
+   > Found `.understand-anything/.understandignore`. Review it if needed, then confirm to continue.
+   - **Wait for user confirmation before proceeding.**
+4. After confirmation, proceed to Phase 1.
+
+---
+
 ## Phase 1 — SCAN (Full analysis only)
 
 Dispatch a subagent using the `project-scanner` agent definition (at `agents/project-scanner.md`). Append the following additional context:
@@ -113,6 +144,9 @@ Store the file list as `$FILE_LIST` with `fileCategory` metadata for use in Phas
 
 **Gate check:** If >100 files, inform the user and suggest scoping with a subdirectory argument. Proceed only if user confirms or add guidance that this may take a while.
 
+If the scan result includes `filteredByIgnore > 0`, report:
+> Excluded {filteredByIgnore} files via `.understandignore`.
+
 ---
 
 ## Phase 2 — ANALYZE