feat(terminal): tint terminal background per agent color

Add backend-agnostic terminal color support via OSC escape sequences:
- New backend/terminal.py with palette_printf() and exec_shell_script()
  shared by both Docker and smolmachines bottle backends
- Emits OSC 4 (indexed palette) + OSC 11 (default background tint)
  before launching; resets both on agent exit via OSC 104/111
- OSC 11 background tint is visible even when the TUI uses true/24-bit
  colors (which bypass the palette), as Codex does for its chrome
- Fix Codex [tui] config: status_line=["model-with-reasoning"],
  theme="ansi" (dark-ansi and cwd/directory were invalid identifiers)

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

bot_bottle/backend/terminal.py

@@ -0,0 +1,82 @@
+"""Terminal escape-sequence helpers shared across all bottle backends."""
+
+from __future__ import annotations
+
+import shlex
+
+
+# color name → (normal_idx, normal_hex, bright_idx, bright_hex, dark_bg_hex)
+# OSC 4 sets indexed palette entries (affects syntax-highlighted code and any
+# TUI content that uses indexed colors).  dark_bg_hex is used for OSC 11
+# (default background) — a very dark tint that's visible even when the TUI
+# uses true/24-bit colors for its own chrome, which would otherwise bypass
+# the palette entirely.
+_COLORS: dict[str, tuple[int, str, int, str, str]] = {
+    "black":          (0,  "#2d2d2d", 8,  "#5c5c5c", "#0a0a0a"),
+    "red":            (1,  "#c0392b", 9,  "#e74c3c", "#1a0707"),
+    "green":          (2,  "#27ae60", 10, "#2ecc71", "#071a09"),
+    "yellow":         (3,  "#d4ac0d", 11, "#f1c40f", "#1a1507"),
+    "blue":           (4,  "#2471a3", 12, "#3498db", "#07071a"),
+    "magenta":        (5,  "#7d3c98", 13, "#9b59b6", "#12071a"),
+    "cyan":           (6,  "#148f77", 14, "#1abc9c", "#071a1a"),
+    "white":          (7,  "#bdc3c7", 15, "#ecf0f1", "#111111"),
+    "bright-black":   (8,  "#5c5c5c", 0,  "#2d2d2d", "#111111"),
+    "bright-red":     (9,  "#e74c3c", 1,  "#c0392b", "#200808"),
+    "bright-green":   (10, "#2ecc71", 2,  "#27ae60", "#082008"),
+    "bright-yellow":  (11, "#f1c40f", 3,  "#d4ac0d", "#201808"),
+    "bright-blue":    (12, "#3498db", 4,  "#2471a3", "#080820"),
+    "bright-magenta": (13, "#9b59b6", 5,  "#7d3c98", "#160820"),
+    "bright-cyan":    (14, "#1abc9c", 6,  "#148f77", "#082020"),
+    "bright-white":   (15, "#ecf0f1", 7,  "#bdc3c7", "#151515"),
+}
+
+# OSC 104 resets all indexed palette entries; OSC 111 resets default background.
+_RESET_PRINTF = "printf '\\033]104\\007\\033]111\\007'"
+
+
+def palette_printf(color: str) -> str:
+    """Shell `printf` command that emits OSC 4 + OSC 11 to tint the terminal
+    for *color*: sets the normal/bright palette entries AND the default
+    background to a dark shade of that color.  Returns '' if unknown."""
+    entry = _COLORS.get(color)
+    if not entry:
+        return ""
+    n_idx, n_hex, b_idx, b_hex, bg_hex = entry
+    seq = (
+        f"\\033]4;{n_idx};{n_hex}\\007"
+        f"\\033]4;{b_idx};{b_hex}\\007"
+        f"\\033]11;{bg_hex}\\007"
+    )
+    return f"printf '{seq}'"
+
+
+def exec_shell_script(
+    agent_argv: list[str],
+    terminal_title: str = "",
+    terminal_color: str = "",
+) -> str | None:
+    """Build a shell script string that optionally sets the terminal
+    title and/or palette before running *agent_argv*, and resets the
+    palette + background on exit. Returns None when no decoration is
+    needed — callers should run *agent_argv* directly in that case."""
+    title_cmd = (
+        f"printf '\\033]0;%s\\007' {shlex.quote(terminal_title)}"
+        if terminal_title else ""
+    )
+    pal_cmd = palette_printf(terminal_color)
+
+    if not title_cmd and not pal_cmd:
+        return None
+
+    parts: list[str] = []
+    if title_cmd:
+        parts.append(title_cmd)
+    if pal_cmd:
+        parts.append(pal_cmd)
+        parts.append(shlex.join(agent_argv))
+        parts.append(_RESET_PRINTF)
+    else:
+        # No palette change — exec so the agent replaces the shell.
+        parts.append(f"exec {shlex.join(agent_argv)}")
+
+    return "; ".join(parts)