Polish chrome and rework tab-switch repaint

Module renamed github.com/harrybrwn/patterm → github.com/hjbdev/patterm
across imports.

Chrome:
- Palette redrawn with rounded box-drawing borders, accent left-bar
  for the selected item, dim hints, and a separator-aware footer.
- Tab bar grew from 1 row to 3: labels with breathing room, a dim
  argv subtitle truncated to each tab's width, and an accent thick
  underline for the focused tab with a faint divider extending across
  the rest of the host width. Layout, viewport-renderer, and screen-
  renderer tests updated for the new mainTop.
- Sidebar reuses the same palette: accent section headers, `▎`
  selection marker, `●`/`○` status glyphs, dim previews.
- Shared SGR constants moved into internal/app/style.go.

Palette input:
- Adjacent duplicate arrow events (legacy `\x1b[B` + kitty
  `\x1b[57353u` for one keypress, or two of the same form) are now
  collapsed via peekArrowEvent + chunk-level dedupe in processStdin.
- On open, push `\x1b[>0u` onto the host's kitty keyboard stack so
  palette input is in plain legacy mode regardless of what the child
  pushed (codex/ratatui pushes its own flags which had been leaking
  to the host). Popped on close.

Tab-switch repaint (repaintFocused):
- Use the emulator's SerializeVT bytes (with SGR / cursor / DECSTBM
  / tabstops) instead of plain text, fed through the per-focused
  viewport renderer so the shifter translates row positions.
- Prelude resets host SGR / DECOM / DECSTBM (pinned to viewport) /
  cursor visibility before the replay, so leftover modes from the
  previously-focused child don't distort the new snapshot.
- Re-emit the saved cursor as a child-space CUP after the
  serialized bytes so the host cursor lands at the emulator's
  actual position (overriding DECSTBM's home side-effect and the
  tabstop-setup CHA sequences) AND the renderer's vr.row/vr.col
  get re-synced via trackCSI.
- cursorShifter now carries childRows and rewrites empty
  `\x1b[r` to `\x1b[<mainTop>;<mainBottom>r` (host coords) — the
  default (1,1) shifted to (4,4) was producing a one-row scrolling
  region that scroll-exploded the replay.
- After the snapshot lands, nudge the focused child with a one-row
  PTY winsize toggle so the kernel emits SIGWINCH and ratatui-style
  TUIs throw away their diff state and emit a fresh frame.

Codex still renders incorrectly after a focus switch; see TODO.md
"Switch-back render divergence" for the deep investigation handoff.

internal/app/child.go

@@ -14,8 +14,8 @@ import (
 	"syscall"
 	"time"
 
-	pkgpty "github.com/harrybrwn/patterm/internal/pty"
-	"github.com/harrybrwn/patterm/internal/vt"
+	pkgpty "github.com/hjbdev/patterm/internal/pty"
+	"github.com/hjbdev/patterm/internal/vt"
 )
 
 // portRegex matches dev-server URLs of the form `http(s)://host:NNNN[/path]`
@@ -374,6 +374,23 @@ func (c *Child) signal(sig syscall.Signal) error {
 	return syscall.Kill(pid, sig)
 }
 
+// NudgeRedraw asks the child to throw away any diff-based render state
+// and emit a full frame on the next tick. Used after a focus switch so
+// ratatui/ink TUIs re-render coherently against the snapshot we just
+// replayed. We toggle the PTY size by one row so the kernel reliably
+// emits SIGWINCH (TIOCSWINSZ skips the signal if the size didn't
+// change). The emulator is left alone — it already matches our intended
+// size and the brief mismatch only affects what the child writes during
+// the second redraw.
+func (c *Child) NudgeRedraw(cols, rows uint16) {
+	pty := c.PTY()
+	if pty == nil || rows < 2 {
+		return
+	}
+	_ = pty.Resize(cols, rows-1)
+	_ = pty.Resize(cols, rows)
+}
+
 func (c *Child) markExited(err error) {
 	exitCode := int32(0)
 	st := StatusExited