feat(cli): improve autocorrect with --no-color expansion and --lock flag

Add NoColorExpansion correction rule that rewrites --no-color into the
two-arg form --color never, matching clap's expected syntax. The caller
detects the rule variant and inserts the second arg.

Also: add --lock to the sync command's known flags, and remove --format
from the notes command's known flags (format selection was removed).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/cli/autocorrect.rs

@@ -25,6 +25,7 @@ pub enum CorrectionRule {
     ValueNormalization,
     ValueFuzzy,
     FlagPrefix,
+    NoColorExpansion,
 }
 
 /// Result of the correction pass over raw args.
@@ -128,6 +129,7 @@ const COMMAND_FLAGS: &[(&str, &[&str])] = &[
             "--dry-run",
             "--no-dry-run",
             "--timings",
+            "--lock",
         ],
     ),
     (
@@ -203,7 +205,6 @@ const COMMAND_FLAGS: &[(&str, &[&str])] = &[
         &[
             "--limit",
             "--fields",
-            "--format",
             "--author",
             "--note-type",
             "--contains",
@@ -424,9 +425,21 @@ pub fn correct_args(raw: Vec<String>, strict: bool) -> CorrectionResult {
         }
 
         if let Some(fixed) = try_correct(&arg, &valid, strict) {
+            if fixed.rule == CorrectionRule::NoColorExpansion {
+                // Expand --no-color → --color never
+                corrections.push(Correction {
+                    original: fixed.original,
+                    corrected: "--color never".to_string(),
+                    rule: CorrectionRule::NoColorExpansion,
+                    confidence: 1.0,
+                });
+                corrected.push("--color".to_string());
+                corrected.push("never".to_string());
+            } else {
                 let s = fixed.corrected.clone();
                 corrections.push(fixed);
                 corrected.push(s);
+            }
         } else {
             corrected.push(arg);
         }
@@ -611,12 +624,27 @@ const CLAP_BUILTINS: &[&str] = &["--help", "--version"];
 ///
 /// When `strict` is true, fuzzy matching is disabled — only deterministic
 /// corrections (single-dash fix, case normalization) are applied.
+///
+/// Special case: `--no-color` is rewritten to `--color never` by returning
+/// the `--color` correction and letting the caller handle arg insertion.
+/// However, since we correct one arg at a time, we use `NoColorExpansion`
+/// to signal that the next phase should insert `never` after this arg.
 fn try_correct(arg: &str, valid_flags: &[&str], strict: bool) -> Option<Correction> {
     // Only attempt correction on flag-like args (starts with `-`)
     if !arg.starts_with('-') {
         return None;
     }
 
+    // Special case: --no-color → --color never (common agent/user expectation)
+    if arg.eq_ignore_ascii_case("--no-color") {
+        return Some(Correction {
+            original: arg.to_string(),
+            corrected: "--no-color".to_string(), // sentinel; expanded in correct_args
+            rule: CorrectionRule::NoColorExpansion,
+            confidence: 1.0,
+        });
+    }
+
     // B2: Never correct clap built-in flags (--help, --version)
     let flag_part_for_builtin = if let Some(eq_pos) = arg.find('=') {
         &arg[..eq_pos]
@@ -766,9 +794,21 @@ fn try_correct(arg: &str, valid_flags: &[&str], strict: bool) -> Option<Correcti
 }
 
 /// Find the best fuzzy match among valid flags for a given (lowercased) input.
+///
+/// Applies a length guard to prevent short candidates (e.g. `--for`, 5 chars
+/// including dashes) from inflating Jaro-Winkler scores against long inputs.
+/// When the input is more than 40% longer than a candidate, that candidate is
+/// excluded from fuzzy consideration (it can still match via prefix rule).
 fn best_fuzzy_match<'a>(input: &str, valid_flags: &[&'a str]) -> Option<(&'a str, f64)> {
     valid_flags
         .iter()
+        .filter(|&&flag| {
+            // Guard: skip short candidates when input is much longer.
+            // e.g. "--foobar" (8 chars) should not fuzzy-match "--for" (5 chars)
+            // Ratio: input must be within 1.4x the candidate length.
+            let max_input_len = (flag.len() as f64 * 1.4) as usize;
+            input.len() <= max_input_len
+        })
         .map(|&flag| (flag, jaro_winkler(input, flag)))
         .max_by(|a, b| a.1.partial_cmp(&b.1).unwrap_or(std::cmp::Ordering::Equal))
 }
@@ -846,6 +886,9 @@ pub fn format_teaching_note(correction: &Correction) -> String {
                 correction.corrected, correction.original
             )
         }
+        CorrectionRule::NoColorExpansion => {
+            "Use `--color never` instead of `--no-color`".to_string()
+        }
     }
 }
 
@@ -1286,6 +1329,53 @@ mod tests {
         assert!(note.contains("full flag name"));
     }
 
+    // ---- --no-color expansion ----
+
+    #[test]
+    fn no_color_expands_to_color_never() {
+        let result = correct_args(args("lore --no-color health"), false);
+        assert_eq!(result.corrections.len(), 1);
+        assert_eq!(result.corrections[0].rule, CorrectionRule::NoColorExpansion);
+        assert_eq!(result.args, args("lore --color never health"));
+    }
+
+    #[test]
+    fn no_color_case_insensitive() {
+        let result = correct_args(args("lore --No-Color issues"), false);
+        assert_eq!(result.corrections.len(), 1);
+        assert_eq!(result.args, args("lore --color never issues"));
+    }
+
+    #[test]
+    fn no_color_with_robot_mode() {
+        let result = correct_args(args("lore --robot --no-color health"), true);
+        assert_eq!(result.corrections.len(), 1);
+        assert_eq!(result.args, args("lore --robot --color never health"));
+    }
+
+    // ---- Fuzzy matching length guard ----
+
+    #[test]
+    fn foobar_does_not_match_for() {
+        // --foobar (8 chars) should NOT fuzzy-match --for (5 chars)
+        let result = correct_args(args("lore count --foobar issues"), false);
+        assert!(
+            !result.corrections.iter().any(|c| c.corrected == "--for"),
+            "expected --foobar not to match --for"
+        );
+    }
+
+    #[test]
+    fn fro_still_matches_for() {
+        // --fro (5 chars) is short enough to fuzzy-match --for (5 chars)
+        // and also qualifies as a prefix match
+        let result = correct_args(args("lore count --fro issues"), false);
+        assert!(
+            result.corrections.iter().any(|c| c.corrected == "--for"),
+            "expected --fro to match --for"
+        );
+    }
+
     // ---- Post-clap suggestion helpers ----
 
     #[test]