make analyze-turn work on current turn instead of requiring parameter

Changed analyze-turn to analyze the current turn (from sc.game.Turn())
instead of requiring a -turn parameter. This is much more intuitive:
- Navigate to a turn with 'n' and 'p'
- Run 'analyze-turn' to analyze that position

Updated help text to reflect this simpler usage.

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

Author: domino14

shell/analyze.go

@@ -233,7 +233,7 @@ func formatPlayerSummaries(summaries [2]*gameanalysis.PlayerSummary) string {
 	return sb.String()
 }
 
-// analyzeTurn analyzes a single turn in the loaded game
+// analyzeTurn analyzes the current turn in the loaded game
 func (sc *ShellController) analyzeTurn(cmd *shellcmd) (*Response, error) {
 	if sc.game == nil {
 		return nil, errors.New("no game loaded; please load a game first with 'load'")
@@ -244,14 +244,10 @@ func (sc *ShellController) analyzeTurn(cmd *shellcmd) (*Response, error) {
 		return nil, errors.New("no game history to analyze")
 	}
 
-	// Get turn number (required)
-	turnNumOpt, err := cmd.options.Int("turn")
-	if err != nil || turnNumOpt < 0 {
-		return nil, errors.New("please specify -turn <number> (0-indexed event number)")
-	}
-
+	// Get current turn number
+	turnNumOpt := sc.game.Turn()
 	if turnNumOpt >= len(history.Events) {
-		return nil, fmt.Errorf("turn %d out of range (game has %d events)", turnNumOpt, len(history.Events))
+		return nil, fmt.Errorf("current turn %d is out of range (game has %d events)", turnNumOpt, len(history.Events))
 	}
 
 	// Create analyzer

shell/helptext/analyze-turn.txt

@@ -1,15 +1,12 @@
-analyze-turn -turn <n>
+analyze-turn
 
-Analyzes a single turn in the loaded game.
+Analyzes the current turn in the loaded game.
 
-Options:
-  -turn <n>  Turn number to analyze (0-indexed event number)
-
-This command analyzes just one specific turn instead of the entire game,
+This command analyzes just the current turn instead of the entire game,
 which is much faster for debugging or examining specific positions.
 
-The turn number is the 0-indexed event number from the game history.
-Use 'list' to see all events and their numbers.
+Use 'n' and 'p' to navigate to different turns, then run analyze-turn
+to see the analysis for that position.
 
 The analysis shows:
   - Player's rack and the move they played

shell/helptext/usage-standard.txt

@@ -34,7 +34,7 @@ Examining a game:
     explain [options] - generate AI explanation for current position
     challenge [n] - add a challenge bonus to the last play of n points, or challenge play off.
     analyze [options] - analyze all moves in the loaded game
-    analyze-turn -turn <n> - analyze a single turn in the game
+    analyze-turn - analyze the current turn
     analyze-batch <filepath> - analyze multiple games from a directory
 Other:
     export <filepath> - export a game to .gcg