fix: write session end hook output to /dev/tty

Claude Code started capturing stderr from SessionEnd hooks instead of
passing it through to the terminal, making the output invisible on macOS.
Write directly to /dev/tty to bypass the capture, with stderr fallback
for Windows where /dev/tty doesn't exist.

Author: backstabslash

CLAUDE.md

@@ -42,7 +42,7 @@ Claude Code stores logs at `~/.claude/projects/<project-slug>/`. Sessions are `<
 - **Local timezone everywhere** — local midnight for cutoffs, `parsed.Local()` for date bucketing. Never `UTC()` for user-facing dates
 - **MCP detection is best-effort** — returns nil/empty on error; statusline never fails due to missing config
 - **Config** — `~/.goccc.json` stores currency, thresholds, and statusline config. `initConfig()` loads once. JSON output costs always in USD
-- **Session end hook** — uses `os.Exit(2)` + ANSI escape to overwrite Claude Code's "hook failed" prefix. Silently exits on any error
+- **Session end hook** — writes to `/dev/tty` (bypasses Claude Code's stderr capture), falls back to stderr on Windows. Silently exits on any error
 - **Statusline segments** — registry in `statusline_config.go`. Segments with no data auto-hide. `"|"` forces line break
 
 ## Don't

statusline.go

@@ -307,8 +307,13 @@ func runSessionEnd(baseDir string) {
 	}
 
 	line := formatSessionEnd(sCost, tCost, reqs, dur, models)
-	// ANSI: erase line + carriage return to overwrite Claude Code's
-	// "SessionEnd hook [...] failed: " prefix before our content.
-	fmt.Fprintf(os.Stderr, "\x1b[2K\r\n%s", line)
+	// Write to /dev/tty to bypass Claude Code's stderr capture.
+	// Falls back to stderr for platforms without /dev/tty (Windows).
+	w := os.Stderr
+	if tty, err := os.OpenFile("/dev/tty", os.O_WRONLY, 0); err == nil {
+		w = tty
+		defer func() { _ = tty.Close() }()
+	}
+	_, _ = fmt.Fprintf(w, "\x1b[2K\r\n%s\n", line)
 	os.Exit(2)
 }