feat(ui): add ai settings web interface for repos and orgs

Add comprehensive web UI for configuring AI features at repository and organization levels, completing the activation workflow for AI operations.

Repository AI Settings (repo/settings/ai):
- Enable/disable AI unit for the repository
- Toggle Tier 1 operations (auto-respond, auto-review, auto-triage, workflow inspection)
- Configure Tier 2 agent mode with trigger labels and runtime limits
- Set escalation rules (label, team assignment)
- Override provider/model preferences
- Add custom instructions for different operation types

Organization AI Settings (org/settings/ai):
- Configure org-level AI provider and model
- Set encrypted API key (with masked display)
- Define rate limits (max operations per hour)
- Whitelist allowed operations
- Enable/disable agent mode for org repositories

Both interfaces include proper permission checks, form validation, and cascade resolution display (showing inherited vs. overridden values). Adds navigation entries to settings sidebars and full i18n support.

modules/ai/types.go

@@ -187,21 +187,31 @@ type SummarizeChangesResponse struct {
 	ImpactAssessment string   `json:"impact_assessment"`
 }
 
+// IssueComment represents a comment on an issue for AI context
+type IssueComment struct {
+	Author    string `json:"author"`
+	Body      string `json:"body"`
+	CreatedAt string `json:"created_at,omitempty"`
+}
+
 // GenerateIssueResponseRequest is the request for generating an AI response to an issue
 type GenerateIssueResponseRequest struct {
-	RepoID             int64  `json:"repo_id"`
-	IssueID            int64  `json:"issue_id"`
-	Title              string `json:"title"`
-	Body               string `json:"body"`
-	CustomInstructions string `json:"custom_instructions,omitempty"`
+	RepoID             int64          `json:"repo_id"`
+	IssueID            int64          `json:"issue_id"`
+	Title              string         `json:"title"`
+	Body               string         `json:"body"`
+	Comments           []IssueComment `json:"comments,omitempty"`
+	ResponseType       string         `json:"response_type,omitempty"` // clarification, solution, acknowledgment
+	CustomInstructions string         `json:"custom_instructions,omitempty"`
 }
 
 // GenerateIssueResponseResponse is the response from generating an issue response
 type GenerateIssueResponseResponse struct {
-	Response     string `json:"response"`
-	Confidence   float64 `json:"confidence"`
-	InputTokens  int    `json:"input_tokens"`
-	OutputTokens int    `json:"output_tokens"`
+	Response            string   `json:"response"`
+	FollowUpQuestions   []string `json:"follow_up_questions,omitempty"`
+	Confidence          float64  `json:"confidence"`
+	InputTokens         int      `json:"input_tokens"`
+	OutputTokens        int      `json:"output_tokens"`
 }
 
 // HealthCheckResponse is the response from a health check