Assign readable ticket keys from project code and sequence.

Replace UUID-looking sync labels in TUI and web with keys like TAS-1,
while keeping the remote UUID for task-master matching.

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/sqlite/projectcode.go

@@ -0,0 +1,49 @@
+package sqlite
+
+import (
+	"fmt"
+	"strings"
+	"unicode"
+)
+
+// DeriveProjectCode builds a 3-letter uppercase code from a project name.
+// Non-letters are skipped; short results are padded with X.
+func DeriveProjectCode(name string) string {
+	var b strings.Builder
+	for _, r := range strings.ToUpper(name) {
+		if unicode.IsLetter(r) && r < unicode.MaxASCII {
+			b.WriteRune(r)
+			if b.Len() == 3 {
+				break
+			}
+		}
+	}
+	code := b.String()
+	for len(code) < 3 {
+		code += "X"
+	}
+	return code
+}
+
+// nextUniqueCode returns base or a nearby 3-char variant until unused.
+// used maps existing codes (uppercase) → true.
+func nextUniqueCode(base string, used map[string]bool) string {
+	base = DeriveProjectCode(base)
+	if !used[base] {
+		return base
+	}
+	prefix := base[:2]
+	for _, c := range "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789" {
+		cand := prefix + string(c)
+		if !used[cand] {
+			return cand
+		}
+	}
+	for i := 0; i < 1000; i++ {
+		cand := fmt.Sprintf("%c%02d", base[0], i)
+		if !used[cand] {
+			return cand
+		}
+	}
+	return fmt.Sprintf("X%02d", len(used)%100)
+}