feat(experimental): add reveal_hidden_cursor_for_cjk_ime opt-in for CJK IME tracking

When the focused pane requests ?25l (cursor hidden) but paints its own
cursor — common in TUIs like Claude Code, pi, and codex — macOS native
input methods stop tracking the candidate-window position. CJK users
(Chinese / Japanese / Korean) cannot see candidate windows follow as
they type. Setting [experimental] reveal_hidden_cursor_for_cjk_ime = true
exposes the focused pane's cursor anchor to the outer terminal regardless
of the pane's hidden-cursor request, restoring IME tracking for CJK input.

[experimental] cjk_ime_agents is an optional allow-list. When empty,
the reveal applies to any focused pane. When non-empty (e.g.
["claude", "codex"]), the reveal only applies if the focused pane's
detected agent matches one of the listed names. This lets users enable
the workaround only for AI-agent TUIs that paint their own cursor,
leaving plain shells and other programs untouched. Accepted names: pi,
claude, codex, gemini, cursor, cline, opencode, copilot, kimi, kiro,
droid, amp, grok, hermes. Unknown names are ignored.

When the pane reports no cursor position (cursor_state returns None for
some TUIs), the anchor falls back to the pane's top-left so a stable
IME hint is always available.

[experimental] cjk_ime_cursor_shape (default "steady_block") controls
the DECSCUSR shape rendered for the revealed cursor; six variants are
accepted: block, steady_block, underline, steady_underline, bar,
steady_bar.

Trade-off when enabled: a hardware cursor will be visible in the outer
terminal for apps that hide the cursor without painting a replacement.
Default false preserves the behavior set in 2c95071. Pair the reveal
with cjk_ime_agents to scope it to specific TUIs.

Manually verified on macOS 26.5 aarch64 with system Pinyin IME against
Claude Code: candidate window tracks cursor with flag enabled, returns
to anchored-at-start behavior with flag disabled.

refs #149

1 files changed, 96 insertions, 0 deletions

diff --git a/src/config/model.rs b/src/config/model.rs
index f0557072..ba52d579 100644
--- a/src/config/model.rs
+++ b/src/config/model.rs
@@ -209,6 +209,33 @@ pub struct UiConfig {
     pub sound: SoundConfig,
 }
 
+/// Cursor shape (DECSCUSR) used for the forced IME anchor.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum ImeCursorShape {
+    Block,
+    #[default]
+    SteadyBlock,
+    Underline,
+    SteadyUnderline,
+    Bar,
+    SteadyBar,
+}
+
+impl ImeCursorShape {
+    /// Convert to DECSCUSR parameter (1–6).
+    pub fn to_decscusr(self) -> u8 {
+        match self {
+            Self::Block => 1,
+            Self::SteadyBlock => 2,
+            Self::Underline => 3,
+            Self::SteadyUnderline => 4,
+            Self::Bar => 5,
+            Self::SteadyBar => 6,
+        }
+    }
+}
+
 #[derive(Debug, Deserialize)]
 #[serde(default)]
 pub struct AdvancedConfig {
@@ -224,6 +251,27 @@ pub struct ExperimentalConfig {
     pub allow_nested: bool,
     /// Experimental local Kitty graphics rendering for attached clients. Default: false.
     pub kitty_graphics: bool,
+    /// Expose the focused pane's cursor anchor to the outer terminal even when
+    /// the pane requested `?25l`, so macOS native input methods keep tracking
+    /// the candidate window when TUIs paint their own cursor (Claude Code, pi,
+    /// codex, etc.). Default: false.
+    ///
+    /// When the pane reports no cursor position, falls back to the pane's
+    /// top-left so a stable IME anchor is always available.
+    ///
+    /// Trade-off when enabled: an extra hardware cursor will be visible in the
+    /// outer terminal for apps that hide the cursor without painting a
+    /// replacement (vim normal mode, etc.). See #149.
+    pub reveal_hidden_cursor_for_cjk_ime: bool,
+    /// Restrict `reveal_hidden_cursor_for_cjk_ime` to focused panes whose
+    /// detected agent matches one of these names (case-insensitive). Empty
+    /// list means apply to any focused pane. Unknown agent names are ignored.
+    /// Accepted names: pi, claude, codex, gemini, cursor, cline, opencode,
+    /// copilot, kimi, kiro, droid, amp, grok, hermes. Default: empty.
+    pub cjk_ime_agents: Vec<String>,
+    /// Cursor shape rendered for the IME anchor when
+    /// `reveal_hidden_cursor_for_cjk_ime` is enabled. Default: "steady_block".
+    pub cjk_ime_cursor_shape: ImeCursorShape,
 }
 
 impl Default for KeysConfig {
@@ -381,6 +429,54 @@ prompt_new_tab_name = false
     }
 
     #[test]
+    fn reveal_hidden_cursor_for_cjk_ime_default_off_and_parse() {
+        let default_config = Config::default();
+        assert!(!default_config.experimental.reveal_hidden_cursor_for_cjk_ime);
+
+        let toml = r#"
+[experimental]
+reveal_hidden_cursor_for_cjk_ime = true
+"#;
+        let config: Config = toml::from_str(toml).unwrap();
+        assert!(config.experimental.reveal_hidden_cursor_for_cjk_ime);
+    }
+
+    #[test]
+    fn cjk_ime_cursor_shape_default_steady_block_and_parse() {
+        let default_config = Config::default();
+        assert_eq!(
+            default_config.experimental.cjk_ime_cursor_shape,
+            ImeCursorShape::SteadyBlock
+        );
+
+        let toml = r#"
+[experimental]
+cjk_ime_cursor_shape = "bar"
+"#;
+        let config: Config = toml::from_str(toml).unwrap();
+        assert_eq!(
+            config.experimental.cjk_ime_cursor_shape,
+            ImeCursorShape::Bar
+        );
+    }
+
+    #[test]
+    fn cjk_ime_agents_default_empty_and_parse() {
+        let default_config = Config::default();
+        assert!(default_config.experimental.cjk_ime_agents.is_empty());
+
+        let toml = r#"
+[experimental]
+cjk_ime_agents = ["claude", "codex"]
+"#;
+        let config: Config = toml::from_str(toml).unwrap();
+        assert_eq!(
+            config.experimental.cjk_ime_agents,
+            vec!["claude".to_string(), "codex".to_string()]
+        );
+    }
+
+    #[test]
     fn sidebar_bounds_default_and_parse() {
         let default_config = Config::default();
         assert_eq!(default_config.ui.sidebar_min_width, 18);