fix(pets): render half-blocks in the VS Code/Cursor terminal

detect_terminal_graphics() mapped TERM_PROGRAM=vscode to the iTerm2 inline
image protocol, but the integrated terminal doesn't render inline images
unless terminal.integrated.enableImages is on — so `hermes pets show`
emitted image escapes xterm.js silently drops, leaving just the label.
It also inherits ITERM_SESSION_ID/KITTY_WINDOW_ID when launched from those
terminals, which false-positived the same way.

Trust the authoritative TERM_PROGRAM=vscode and fall back to truecolor
half-blocks (always renderable in its grid); users who enabled images can
still pin display.pet.render_mode explicitly.

agent/pet/render.py

@@ -7,7 +7,7 @@ decode + capability-detection + protocol-encoding logic exists exactly once.
 Supported output modes, in fidelity order:
 
 - ``kitty``   — the kitty graphics protocol (kitty, Ghostty, WezTerm).
-- ``iterm``   — iTerm2 inline images (iTerm2, WezTerm, VS Code terminal).
+- ``iterm``   — iTerm2 inline images (iTerm2, WezTerm).
 - ``sixel``   — DEC sixel (xterm -ti vt340, foot, mlterm, WezTerm, …).
 - ``unicode`` — 24-bit half-block downscale; works in any truecolor terminal.
 
@@ -56,6 +56,17 @@ def detect_terminal_graphics() -> str:
     term = os.environ.get("TERM", "").lower()
     term_program = os.environ.get("TERM_PROGRAM", "").lower()
 
+    # The VS Code / Cursor integrated terminal sets TERM_PROGRAM=vscode
+    # authoritatively but does NOT scrub the terminal env vars it inherits when
+    # launched from another emulator (ITERM_SESSION_ID, KITTY_WINDOW_ID, …).
+    # Trusting those leaks emits an image protocol the embedded xterm.js can't
+    # display — you get a blank frame. Inline images there are opt-in
+    # (terminal.integrated.enableImages), so default to half-blocks, which
+    # always render in its truecolor grid. Users who enabled images can pin
+    # display.pet.render_mode explicitly.
+    if term_program == "vscode":
+        return "unicode"
+
     # kitty graphics protocol
     if os.environ.get("KITTY_WINDOW_ID") or "kitty" in term or "ghostty" in term:
         return "kitty"
@@ -69,8 +80,6 @@ def detect_terminal_graphics() -> str:
     # iTerm2 inline images
     if term_program == "iterm.app" or os.environ.get("ITERM_SESSION_ID"):
         return "iterm"
-    if term_program == "vscode":
-        return "iterm"
 
     # sixel-capable terminals (env heuristics only)
     if term_program in {"mintty"} or "foot" in term or "mlterm" in term:

tests/agent/test_pet_engine.py

@@ -177,3 +177,19 @@ def test_detect_terminal_graphics_env(monkeypatch):
 
     monkeypatch.setenv("TERM", "xterm-256color")
     assert render.detect_terminal_graphics() == "unicode"
+
+
+def test_vscode_terminal_ignores_leaked_graphics_env(monkeypatch):
+    # The VS Code / Cursor integrated terminal can't show inline images by
+    # default, yet inherits ITERM_SESSION_ID/KITTY_WINDOW_ID when launched from
+    # those terminals. TERM_PROGRAM=vscode must win → unicode, never a protocol
+    # whose escapes the embedded terminal would silently drop.
+    for key in ("KITTY_WINDOW_ID", "TERM_PROGRAM", "ITERM_SESSION_ID", "WEZTERM_PANE", "TERM"):
+        monkeypatch.delenv(key, raising=False)
+    monkeypatch.setenv("TERM_PROGRAM", "vscode")
+
+    assert render.detect_terminal_graphics() == "unicode"
+    for leaked in ("ITERM_SESSION_ID", "KITTY_WINDOW_ID", "WEZTERM_PANE"):
+        monkeypatch.setenv(leaked, "1")
+        assert render.detect_terminal_graphics() == "unicode"
+        monkeypatch.delenv(leaked)