docs(prompt): clarify scope must not repeat commit type

Author: nikmd1306

internal/ai/schema.go

@@ -55,7 +55,7 @@ func BuildResponseFormat() map[string]any {
 					},
 					"scope": map[string]any{
 						"type":        "string",
-						"description": "Exactly ONE word, no spaces. Good: auth, api, db, ui. Bad: 'auth system'.",
+						"description": "Exactly ONE word, no spaces. MUST NOT repeat the commit type. Good: auth, api, db, ui. Bad: 'auth system', 'tests' when type is test, 'docs' when type is docs.",
 					},
 					"description": map[string]any{
 						"type":        "string",

internal/prompt/prompt.go

@@ -13,7 +13,7 @@ FORMAT RULES:
    - <specific change 2>
 
 2. Type MUST be one of: feat, fix, refactor, docs, style, test, chore, perf, ci, build
-3. Scope is REQUIRED — short, generalizing word covering ALL changes
+3. Scope is REQUIRED — short, generalizing word covering ALL changes. Scope MUST NOT repeat the type (BAD: test(tests), ci(ci), docs(docs). GOOD: test(auth), ci(github), docs(readme)).
 4. Description: lowercase, imperative mood, no period, max 72 chars first line
 5. Bullet points when 3+ distinct changes. No bullet points for trivial changes.
 6. Output ONLY the commit message. No explanations, no formatting, no quotes.