fix(logging): simplify tty color detection

docs/configuration.md

@@ -49,7 +49,6 @@ If set, CLAWDIS derives defaults (only when you haven’t set them explicitly):
 - Console output can be tuned separately via:
   - `logging.consoleLevel` (defaults to `info`, bumps to `debug` when `--verbose`)
   - `logging.consoleStyle` (`pretty` | `compact` | `json`)
-  - `logging.consoleColor` (`auto` | `always` | `never`)
 
 ```json5
 {
@@ -57,8 +56,7 @@ If set, CLAWDIS derives defaults (only when you haven’t set them explicitly):
     level: "info",
     file: "/tmp/clawdis/clawdis.log",
     consoleLevel: "info",
-    consoleStyle: "pretty",
-    consoleColor: "auto"
+    consoleStyle: "pretty"
   }
 }
 ```

docs/logging.md

@@ -75,7 +75,7 @@ Behavior:
 
 - **Subsystem prefixes** on every line (e.g. `[gateway]`, `[canvas]`, `[tailscale]`)
 - **Subsystem colors** (stable per subsystem) plus level coloring
-- **Color modes** (`logging.consoleColor`: `auto`/`always`/`never`; `auto` honors `NO_COLOR` and TTY)
+- **Color only when TTY** (`process.stdout.isTTY`/`process.stderr.isTTY`), respects `NO_COLOR`
 - **Sub-loggers by subsystem** (auto prefix + structured field `{ subsystem }`)
 - **`logRaw()`** for QR/UX output (no prefix, no formatting)
 - **Console styles** (e.g. `pretty | compact | json`)