feat: anti-detection hardening, transaction cache, article parsing, structured write output

Anti-detection:
- Add 6 sec-ch-ua-* Client Hints headers (arch, bitness, full-version, etc.)
- POST requests now send Referer: x.com/compose/post + Priority: u=1, i
- follow/unfollow REST adds include_profile_interstitial_type param

Performance:
- Transaction ID cache with 1h TTL (~/.twitter-cli/transaction_cache.json)
- resolve_user_id: auto-detect screen_name vs numeric user_id

Features:
- Twitter Article parsing: extract long-form content as Markdown
- Write operations emit structured JSON/YAML when piped or OUTPUT env set
  ActionResult: {success, action, id, url, ...}

84 tests passing

twitter_cli/output.py

@@ -0,0 +1,68 @@
+"""Shared structured output helpers for twitter-cli."""
+
+from __future__ import annotations
+
+import json
+import os
+import sys
+from typing import Any, Callable
+
+import click
+import yaml
+
+_OUTPUT_ENV = "OUTPUT"
+
+
+def default_structured_format(*, as_json: bool, as_yaml: bool) -> str | None:
+    """Resolve explicit flags first, then env override, then TTY default."""
+    if as_json and as_yaml:
+        raise click.UsageError("Use only one of --json or --yaml.")
+    if as_yaml:
+        return "yaml"
+    if as_json:
+        return "json"
+
+    output_mode = os.getenv(_OUTPUT_ENV, "auto").strip().lower()
+    if output_mode == "yaml":
+        return "yaml"
+    if output_mode == "json":
+        return "json"
+    if output_mode == "rich":
+        return None
+
+    if not sys.stdout.isatty():
+        return "yaml"
+    return None
+
+
+def use_rich_output(*, as_json: bool, as_yaml: bool, compact: bool = False) -> bool:
+    """Return True when human-readable rich output should be used."""
+    if compact:
+        return False
+    return default_structured_format(as_json=as_json, as_yaml=as_yaml) is None
+
+
+def structured_output_options(command: Callable) -> Callable:
+    """Add --json/--yaml options to a Click command."""
+    command = click.option("--yaml", "as_yaml", is_flag=True, help="Output as YAML.")(command)
+    command = click.option("--json", "as_json", is_flag=True, help="Output as JSON.")(command)
+    return command
+
+
+def emit_structured(data: Any, *, as_json: bool, as_yaml: bool) -> bool:
+    """Emit structured output and return True when used."""
+    fmt = default_structured_format(as_json=as_json, as_yaml=as_yaml)
+    if not fmt:
+        return False
+    if fmt == "json":
+        click.echo(json.dumps(data, ensure_ascii=False, indent=2))
+    else:
+        click.echo(
+            yaml.safe_dump(
+                data,
+                allow_unicode=True,
+                sort_keys=False,
+                default_flow_style=False,
+            )
+        )
+    return True