test(gateway): pin routine-suppression + visible-carve-out contracts

- Iterate ROUTINE_COMPRESSION_STATUS_SAMPLES (formatted from the source
  constants the emit sites use) through _prepare_gateway_status_message on
  every chat platform — emission-wording drift now fails the suite without
  re-copying literals.
- Extend the pinned NOISY_STATUS_MESSAGES with the buffered retry chatter
  and post-#69332 wordings.
- New VISIBLE_COMPRESSION_MESSAGES negative suite: manual /compress
  headlines and abort/failure notices must never be swallowed by the
  widened regex.

tests/gateway/test_telegram_noise_filter.py

@@ -2,6 +2,7 @@
 
 import pytest
 
+from agent.conversation_compression import ROUTINE_COMPRESSION_STATUS_SAMPLES
 from gateway.config import Platform
 from gateway.run import (
     _prepare_gateway_status_message,
@@ -40,6 +41,47 @@ NOISY_STATUS_MESSAGES = [
     "⚠ Compression summary failed: upstream error. Inserted a fallback context marker.",
     "⏱️ Rate limited. Waiting 30.0s (attempt 2/3)...",
     "⏳ Retrying in 4.2s (attempt 1/3)...",
+    # Buffered overflow/attempt-cap retry chatter (replayed on retry exhaustion).
+    "🗜️ Context too large (~250,000 tokens) — compressing (1/3)...",
+    "🗜️ Compressed 30 → 12 messages, retrying...",
+    "🗜️ Compressed ~250,000 → ~120,000 tokens, retrying...",
+    "🗜️ Context reduced to 120,000 tokens (was 250,000), retrying...",
+    # Post-#69332 auto-lower wording + aux-provider/lock chatter.
+    (
+        "⚠ Compression model small (openrouter) context is 32,000 tokens, but "
+        "the main model big (anthropic)'s compression threshold was 100,000 "
+        "tokens. Auto-lowered this session's threshold to 30,000 tokens so "
+        "compression can run."
+    ),
+    (
+        "⚠ Configured auxiliary compression provider 'openai' is unavailable — "
+        "context compression will drop middle turns without a summary. Check "
+        "auxiliary.compression in config.yaml and reauthenticate that provider."
+    ),
+    (
+        "⚠ Skipping concurrent compression — another path is already "
+        "compressing this session. Will retry after it finishes."
+    ),
+]
+
+# Messages that must NEVER be swallowed by the compression-noise filter:
+# deliberate carve-outs from routine-compression silence — manual /compress
+# feedback (manual_compression_feedback.py headlines) and abort/failure
+# notices that require user action.
+VISIBLE_COMPRESSION_MESSAGES = [
+    "Compressed: 30 → 12 messages",
+    "Compression aborted: 30 messages preserved",
+    "Compressed with fallback: 30 → 12 messages",
+    "No changes from compression: 30 messages",
+    (
+        "⚠ Compression aborted: auth failure. No messages were dropped — "
+        "conversation continues unchanged. Run /compress to retry, or /new "
+        "to start a fresh session."
+    ),
+    (
+        "⚠ Compression returned an empty transcript. No session split was "
+        "performed; conversation continues unchanged."
+    ),
 ]
 
 
@@ -86,6 +128,36 @@ def test_all_chat_gateways_suppress_noise(platform, message):
     assert _prepare_gateway_status_message(platform, "warn", message) is None
 
 
+@pytest.mark.parametrize("platform", CHAT_PLATFORMS)
+@pytest.mark.parametrize(
+    "message", ROUTINE_COMPRESSION_STATUS_SAMPLES, ids=lambda m: m[:32]
+)
+def test_all_routine_compression_statuses_suppressed_from_source_constants(
+    platform, message
+):
+    """Every ROUTINE compression status the agent actually emits is filtered.
+
+    Iterates the sample-formatted status strings built from the SAME
+    constants the emission sites use (agent/conversation_compression.py's
+    ROUTINE_COMPRESSION_STATUS_SAMPLES), so a reworded emit site that drifts
+    past the noise regex fails here without anyone remembering to re-copy
+    the literal into this file.
+    """
+    assert _prepare_gateway_status_message(platform, "lifecycle", message) is None
+
+
+@pytest.mark.parametrize("platform", CHAT_PLATFORMS)
+@pytest.mark.parametrize("message", VISIBLE_COMPRESSION_MESSAGES, ids=lambda m: m[:32])
+def test_manual_compress_feedback_and_failure_notices_stay_visible(platform, message):
+    """Manual /compress feedback and abort notices must never be swallowed.
+
+    These are the deliberate carve-outs from routine-compression silence
+    (#16775 failures, manual_compression_feedback.py) — widening the noise
+    regex must not start eating them.
+    """
+    assert _prepare_gateway_status_message(platform, "warn", message) == message
+
+
 @pytest.mark.parametrize("platform", ["whatsapp", "slack", "signal", "matrix"])
 def test_chat_gateways_redact_secret_in_provider_error(platform):
     """Provider-error bodies carrying secrets must never reach chat users.