Stabilize first-run cudagraph timing and colorize terminal output

- _cudagraph_plugin: warm up autotune/JIT explicitly before graph capture
  (internal 5-iter warmup is too short), tag fallback markers with the
  failing phase; first-run latency no longer jitters run-to-run.
- _device_guard_plugin (new): set GEMS_VENDOR via torch probe before
  importing flag_gems, avoiding its timeout-less nvidia-smi subprocess
  probe that can hang import in fork-broken environments.
- _pretty_report_plugin (new) + _term_style (new): fold inputs identical
  across all result rows into a legend line, color status/plugin
  tags/markers on the live terminal; run.log is ANSI-stripped and keeps
  upstream SUCCESS/column wording for grep compatibility.
- run_pytest.sh: make USE_FLAGTUNE overridable, group all knobs into a
  config section with Chinese comments, add start/end banners.
- README: document the warmup semantics, new plugins/env vars, and the
  A/B rule that both sides must use the same USE_FLAGTUNE.

_ir_meta_plugin.py

@@ -114,7 +114,8 @@ def _compile_listener(*, src, metadata, metadata_group, times, cache_hit):
                       f, indent=1, sort_keys=True)
         os.replace(tmp, path)
     except Exception as exc:  # never break compilation over a metadata dump
-        print(f"[ir-meta-plugin] sidecar dump failed: {exc}", file=sys.stderr)
+        from _term_style import tag
+        print(f"{tag('[ir-meta-plugin]')} sidecar dump failed: {exc}", file=sys.stderr)
 
 
 # --- shape + launch tracking ----------------------------------------------
@@ -202,7 +203,8 @@ def pytest_collection_finish(session):
         if own is not None:
             cls.get_input_iter = _wrap_input_iter(own)
             wrapped += 1
-    print(f"[ir-meta-plugin] shape tracking wrapped on {wrapped} Benchmark classes",
+    from _term_style import tag
+    print(f"{tag('[ir-meta-plugin]')} shape tracking wrapped on {wrapped} Benchmark classes",
           file=sys.stderr, flush=True)
 
 
@@ -312,7 +314,9 @@ def _dump_ttgir(cache_dir: str, dump_dir: str) -> None:
 
     cache, dest = pathlib.Path(cache_dir), pathlib.Path(dump_dir)
     if not cache.is_dir():
-        print(f"[ir-meta-plugin] no cache dir {cache}; nothing to dump", file=sys.stderr)
+        from _term_style import tag
+        print(f"{tag('[ir-meta-plugin]')} no cache dir {cache}; nothing to dump",
+              file=sys.stderr)
         return
     dest.mkdir(parents=True, exist_ok=True)
 
@@ -386,11 +390,12 @@ def _dump_ttgir(cache_dir: str, dump_dir: str) -> None:
 
     shapes = sorted({r[0] for r in rows if r[0] != "-"})
     losers = sum(1 for r in rows if r[0] == "-")
+    from _term_style import DIM, paint
     print(f">>> [Dump] ttgir -> {dest} ({copied} files across {len(shapes)} shapes; "
           f"{losers} unused variants index-only; legend: naming.md)", flush=True)
     for s in shapes:
         n = sum(1 for r in rows if r[0] == s)
-        print(f">>> [Dump]   {s}: {n}", flush=True)
+        print(paint(f">>> [Dump]   {s}: {n}", DIM), flush=True)
 
 
 # --- registration -----------------------------------------------------------
@@ -419,10 +424,12 @@ def pytest_configure(config):
             _autotuner.Autotuner._bench = _wrap_bench(_autotuner.Autotuner._bench)
             atexit.register(_dump_ttgir, cache_dir, dump_dir)
         else:
-            print("[ir-meta-plugin] warning: dump dir set but TRITON_CACHE_DIR "
+            from _term_style import tag
+            print(f"{tag('[ir-meta-plugin]')} warning: dump dir set but TRITON_CACHE_DIR "
                   "is not; ttgir dump disabled", file=sys.stderr, flush=True)
 
-    print("[ir-meta-plugin] compilation listener registered"
+    from _term_style import tag
+    print(f"{tag('[ir-meta-plugin]')} compilation listener registered"
           + (f"; shape/launch tracking on, ttgir dump -> {dump_dir}"
              if _dump_enabled else ""),
           file=sys.stderr, flush=True)