refactor: render the shell in the client (#3487)

* feat: add opt-in client-rendered shell

* feat: add client-owned shell mouse controls

* feat: complete client-owned shell chrome

* feat: add client-owned shell settings and notifications

* feat: run client shell custom commands

* feat: render popup terminals in client shell

* feat: add client-owned scrollback and copy mode

* fix: preserve client worktree trust defaults

* feat: render startup diagnostics in client shell

* feat: render onboarding in client shell

* feat: render product announcements in client shell

* feat: render release notes in client shell

* feat: render mobile switcher in client shell

* feat: render kitty graphics in client shell

* fix: preserve client shell lifecycle coherence

* refactor: route client shell commands through endpoint connections

* refactor: make the client-rendered shell the default

* refactor: remove monolithic launch mode

* refactor: complete client-rendered shell cutover

* perf: retain client pane surface updates

* perf: scale retained pane surface updates

* perf: remove remote pane input latency

* test: make client shell checks platform-independent

* fix: prevent client timer starvation

* test: fix client shell platform gates

* test: accept retained surfaces in cross-area checks

* test: make client mode assertions platform-neutral

* fix: badge only outdated integrations

1 files changed, 86 insertions, 0 deletions

diff --git a/src/copy_mode.rs b/src/copy_mode.rs
new file mode 100644
index 00000000..8f84b9a8
--- /dev/null
+++ b/src/copy_mode.rs
@@ -0,0 +1,86 @@
+use crossterm::event::{KeyCode, KeyModifiers};
+
+use crate::input::TerminalKey;
+
+pub(crate) fn first_non_blank_col(text: &str) -> Option<u16> {
+    let mut col = 0u16;
+    for ch in text.chars() {
+        if !ch.is_whitespace() {
+            return Some(col);
+        }
+        col = col.saturating_add(char_cell_width(ch));
+    }
+    None
+}
+
+pub(crate) fn last_character_col(text: &str) -> Option<u16> {
+    let mut col = 0u16;
+    let mut last_col = None;
+    for ch in text.chars() {
+        let width = u16::from(crate::ghostty::unicode_codepoint_width(ch as u32));
+        if width > 0 {
+            last_col = Some(col);
+            col = col.saturating_add(width);
+        }
+    }
+    last_col
+}
+
+fn char_cell_width(ch: char) -> u16 {
+    u16::from(crate::ghostty::unicode_codepoint_width(ch as u32)).max(1)
+}
+
+pub(crate) fn copy_mode_page_lines(height: u16, half_page: bool) -> usize {
+    if height <= 2 {
+        1
+    } else if half_page {
+        usize::from(height / 2)
+    } else {
+        usize::from(height - 2)
+    }
+}
+
+pub(crate) fn copy_mode_command_char(key: TerminalKey) -> Option<char> {
+    if !key.modifiers.difference(KeyModifiers::SHIFT).is_empty() {
+        return None;
+    }
+    if let Some(ch) = key.shifted_codepoint.and_then(char::from_u32) {
+        return Some(ch);
+    }
+    let KeyCode::Char(ch) = key.code else {
+        return None;
+    };
+    if key.modifiers.contains(KeyModifiers::SHIFT) {
+        Some(shifted_ascii_char(ch).unwrap_or(ch))
+    } else {
+        Some(ch)
+    }
+}
+
+fn shifted_ascii_char(ch: char) -> Option<char> {
+    match ch {
+        'a'..='z' => Some(ch.to_ascii_uppercase()),
+        '1' => Some('!'),
+        '2' => Some('@'),
+        '3' => Some('#'),
+        '4' => Some('$'),
+        '5' => Some('%'),
+        '6' => Some('^'),
+        '7' => Some('&'),
+        '8' => Some('*'),
+        '9' => Some('('),
+        '0' => Some(')'),
+        '-' => Some('_'),
+        '=' => Some('+'),
+        '[' => Some('{'),
+        ']' => Some('}'),
+        '\\' => Some('|'),
+        ';' => Some(':'),
+        '\'' => Some('"'),
+        ',' => Some('<'),
+        '.' => Some('>'),
+        '/' => Some('?'),
+        '`' => Some('~'),
+        _ => None,
+    }
+}