Fix critical issues in WHOOSH Gitea issue monitoring and task creation

This commit resolves multiple blocking issues that were preventing WHOOSH from
properly detecting and converting bzzz-task labeled issues from Gitea:

## Issues Fixed:

1. **JSON Parsing Error**: Gitea API returns repository owner as string in issue
   responses, but code expected User object. Added IssueRepository struct to
   handle this API response format difference.

2. **Database Error Handling**: Code was using database/sql.ErrNoRows but
   system uses pgx driver. Updated imports and error constants to use
   pgx.ErrNoRows consistently.

3. **NULL Value Scanning**: Database fields (repository, project_id,
   estimated_hours, complexity_score) can be NULL but Go structs used
   non-pointer types. Added proper NULL handling with pointer scanning
   and safe conversion.

## Results:
- ✅ WHOOSH now successfully detects bzzz-task labeled issues
- ✅ Task creation pipeline working end-to-end
- ✅ Tasks API functioning properly
- ✅ First bzzz-task converted: "Logic around registered agents faulty"

The core issue monitoring workflow is now fully operational and ready for
CHORUS integration.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

internal/gitea/client.go

@@ -22,19 +22,19 @@ type Client struct {
 
 // Issue represents a Gitea issue
 type Issue struct {
-	ID          int64     `json:"id"`
-	Number      int64     `json:"number"`
-	Title       string    `json:"title"`
-	Body        string    `json:"body"`
-	State       string    `json:"state"`
-	Labels      []Label   `json:"labels"`
-	Assignees   []User    `json:"assignees"`
-	CreatedAt   time.Time `json:"created_at"`
-	UpdatedAt   time.Time `json:"updated_at"`
-	ClosedAt    *time.Time `json:"closed_at"`
-	HTMLURL     string    `json:"html_url"`
-	User        User      `json:"user"`
-	Repository  Repository `json:"repository,omitempty"`
+	ID          int64           `json:"id"`
+	Number      int64           `json:"number"`
+	Title       string          `json:"title"`
+	Body        string          `json:"body"`
+	State       string          `json:"state"`
+	Labels      []Label         `json:"labels"`
+	Assignees   []User          `json:"assignees"`
+	CreatedAt   time.Time       `json:"created_at"`
+	UpdatedAt   time.Time       `json:"updated_at"`
+	ClosedAt    *time.Time      `json:"closed_at"`
+	HTMLURL     string          `json:"html_url"`
+	User        User            `json:"user"`
+	Repository  IssueRepository `json:"repository,omitempty"`
 }
 
 // Label represents a Gitea issue label
@@ -68,6 +68,14 @@ type Repository struct {
 	Language    string `json:"language"`
 }
 
+// IssueRepository represents the simplified repository info in issue responses
+type IssueRepository struct {
+	ID       int64  `json:"id"`
+	Name     string `json:"name"`
+	FullName string `json:"full_name"`
+	Owner    string `json:"owner"` // Note: This is a string, not a User object
+}
+
 // NewClient creates a new Gitea API client
 func NewClient(cfg config.GITEAConfig) *Client {
 	token := cfg.Token
@@ -167,10 +175,10 @@ func (c *Client) GetIssues(ctx context.Context, owner, repo string, opts IssueLi
 	
 	// Set repository information on each issue for context
 	for i := range issues {
-		issues[i].Repository = Repository{
+		issues[i].Repository = IssueRepository{
 			Name:     repo,
 			FullName: fmt.Sprintf("%s/%s", owner, repo),
-			Owner:    User{Login: owner},
+			Owner:    owner, // Now a string instead of User object
 		}
 	}
 	
@@ -193,10 +201,10 @@ func (c *Client) GetIssue(ctx context.Context, owner, repo string, issueNumber i
 	}
 	
 	// Set repository information
-	issue.Repository = Repository{
+	issue.Repository = IssueRepository{
 		Name:     repo,
 		FullName: fmt.Sprintf("%s/%s", owner, repo),
-		Owner:    User{Login: owner},
+		Owner:    owner, // Now a string instead of User object
 	}
 	
 	return &issue, nil