refactor: consolidate duplicate path-finding utilities (bd-74w1, bd-4nqq)

- Add git.GetRepoRoot() with Windows path normalization
- Update beads.findGitRoot() to delegate to git.GetRepoRoot()
- Replace findBeadsDir() with beads.FindBeadsDir() across 8 files
- Remove duplicate findBeadsDir() and findGitRoot() function definitions
- Remove dead test code (TestInfoCommand, TestInfoWithNoDaemon)
- Update tests to work with consolidated APIs

Part of Code Health Review Dec 2025 epic (bd-tggf).

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

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

cmd/bd/jira.go

@@ -14,6 +14,7 @@ import (
 	"time"
 
 	"github.com/spf13/cobra"
+	"github.com/steveyegge/beads/internal/beads"
 	"github.com/steveyegge/beads/internal/types"
 )
 
@@ -568,7 +569,7 @@ func findJiraScript(name string) (string, error) {
 	}
 
 	// Check BEADS_DIR or current .beads location
-	if beadsDir := findBeadsDir(); beadsDir != "" {
+	if beadsDir := beads.FindBeadsDir(); beadsDir != "" {
 		repoRoot := filepath.Dir(beadsDir)
 		locations = append(locations, filepath.Join(repoRoot, "examples", "jira-import", name))
 	}