refactor(rules): restructure into common + language-specific directories

* refactor(rules): restructure rules into common + language-specific directories

- Split 8 flat rule files into common/, typescript/, python/, golang/
- common/ contains language-agnostic principles (no code examples)
- typescript/ extracts TS/JS specifics (Zod, Playwright, Prettier hooks, etc.)
- python/ adds Python rules (PEP 8, pytest, black/ruff, bandit)
- golang/ adds Go rules (gofmt, table-driven tests, gosec, functional options)
- Replace deprecated ultrathink with extended thinking documentation
- Add README.md with installation guide and new-language template

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

* Fix installation commands for rules

Updated installation instructions to copy all rules to a single directory.

* docs: update README.md to reflect new rules directory structure

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

---------

Co-authored-by: Hor1zonZzz <Hor1zonZzz@users.noreply.github.com>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

rules/golang/testing.md

@@ -0,0 +1,25 @@
+# Go Testing
+
+> This file extends [common/testing.md](../common/testing.md) with Go specific content.
+
+## Framework
+
+Use the standard `go test` with **table-driven tests**.
+
+## Race Detection
+
+Always run with the `-race` flag:
+
+```bash
+go test -race ./...
+```
+
+## Coverage
+
+```bash
+go test -cover ./...
+```
+
+## Reference
+
+See skill: `golang-testing` for detailed Go testing patterns and helpers.