docs: initialize project and codebase maps

- Finalized PROJECT.md incorporating 'Zero-Pollution' constraints
- Enforced native Git portability (git pull sync only)
- Generated ARCHITECTURE.md and STACK.md maps
- Deleted .agent/skills/.gitignore to physically track flattened skills

.agent/skills/defuddle/SKILL.md

@@ -0,0 +1,41 @@
+---
+name: defuddle
+description: URL 링크를 통해 웹페이지 문서의 군더더기를 제거하고 깔끔한 마크다운 정보만 추출하여 분석합니다.
+---
+
+# Defuddle
+
+Use Defuddle CLI to extract clean readable content from web pages. Prefer over WebFetch for standard web pages — it removes navigation, ads, and clutter, reducing token usage.
+
+If not installed: `npm install -g defuddle`
+
+## Usage
+
+Always use `--md` for markdown output:
+
+```bash
+defuddle parse <url> --md
+```
+
+Save to file:
+
+```bash
+defuddle parse <url> --md -o content.md
+```
+
+Extract specific metadata:
+
+```bash
+defuddle parse <url> -p title
+defuddle parse <url> -p description
+defuddle parse <url> -p domain
+```
+
+## Output formats
+
+| Flag | Format |
+|------|--------|
+| `--md` | Markdown (default choice) |
+| `--json` | JSON with both HTML and markdown |
+| (none) | HTML |
+| `-p <name>` | Specific metadata property |