Add Turkish (tr) docs and update README (#744)

* Add Turkish (tr) docs and update README

Add a full set of Turkish documentation under docs/tr (agents, changelog, CLAUDE guide, contributing, code of conduct, and many agents/commands/skills/rules files). Update README to include a link to the Turkish docs and increment the supported language count from 5 to 6. This commit adds localized guidance and references to help Turkish-speaking contributors and users.

* Update docs/tr/TROUBLESHOOTING.md

Co-authored-by: cubic-dev-ai[bot] <191113872+cubic-dev-ai[bot]@users.noreply.github.com>

* Update docs/tr/README.md

Co-authored-by: cubic-dev-ai[bot] <191113872+cubic-dev-ai[bot]@users.noreply.github.com>

* docs(tr): fix license link and update readmes

Update Turkish docs: change license badge link to point to repository root (../../LICENSE), increment displayed language count from 5 to 6, and remove two outdated related links from docs/tr/examples/README.md to keep references accurate.

* Update docs/tr/commands/instinct-import.md

Co-authored-by: cubic-dev-ai[bot] <191113872+cubic-dev-ai[bot]@users.noreply.github.com>

* Update docs/tr/commands/checkpoint.md

Co-authored-by: cubic-dev-ai[bot] <191113872+cubic-dev-ai[bot]@users.noreply.github.com>

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Co-authored-by: cubic-dev-ai[bot] <191113872+cubic-dev-ai[bot]@users.noreply.github.com>

docs/tr/rules/golang/testing.md

@@ -0,0 +1,31 @@
+---
+paths:
+  - "**/*.go"
+  - "**/go.mod"
+  - "**/go.sum"
+---
+# Go Testing
+
+> Bu dosya [common/testing.md](../common/testing.md) dosyasını Go'ya özgü içerikle genişletir.
+
+## Framework
+
+**Table-driven testler** ile standart `go test` kullan.
+
+## Race Detection
+
+Daima `-race` flag'i ile çalıştır:
+
+```bash
+go test -race ./...
+```
+
+## Coverage
+
+```bash
+go test -cover ./...
+```
+
+## Referans
+
+Detaylı Go test pattern'leri ve helper'lar için skill: `golang-testing` dosyasına bakın.