fix(sidebar): declutter session items — drop message count, model, and source-tag badges (v0.50.64)

Squash-merges PR #584 by @aronprins.

Drops the meta row (message count, model slug, source-tag badge) from every sidebar session item. Each session now renders as a single title line — visible session count roughly doubles at typical viewport height.

Changes merged verbatim from contributor branch, plus maintainer additions:
- CHANGELOG entry for v0.50.64
- Version badge bump to v0.50.64
- New test: test_relative_time_today_bucket (closes minor coverage gap from code review)

Co-authored-by: aronprins <aronprins@users.noreply.github.com>

tests/test_sprint40_ui_polish.py

@@ -118,85 +118,6 @@ class TestGatewaySessionNullModel(unittest.TestCase):
         )
 
 
-if __name__ == "__main__":
-    unittest.main()
-
-# ── #453 telegram badge ─────────────────────────────────────────────
-class TestTelegramBadgeMutedColor(unittest.TestCase):
-
-    def test_telegram_badge_uses_muted_color(self):
-        """Telegram badge rules must use rgba(0, 136, 204, 0.55) not #0088cc."""
-        # Extract only the telegram-related CSS block
-        telegram_lines = [
-            line for line in STYLE_CSS.splitlines()
-            if 'data-source="telegram"' in line or "data-source='telegram'" in line
-        ]
-        self.assertTrue(
-            len(telegram_lines) >= 2,
-            "Expected at least 2 telegram badge CSS rules"
-        )
-        muted_color = "rgba(0, 136, 204, 0.55)"
-        for line in telegram_lines:
-            self.assertIn(
-                muted_color, line,
-                f"Telegram CSS rule should use {muted_color!r}, got: {line!r}"
-            )
-            self.assertNotIn(
-                "#0088cc", line,
-                f"Telegram CSS rule must not use saturated #0088cc, got: {line!r}"
-            )
-
-    def test_telegram_border_left_color_muted(self):
-        """The border-left-color rule for telegram uses rgba."""
-        pattern = r'\.session-item\.cli-session\[data-source=["\']telegram["\']\]\s*\{[^}]*border-left-color:\s*rgba\(0,\s*136,\s*204,\s*0\.55\)'
-        self.assertRegex(STYLE_CSS, pattern,
-            "border-left-color for telegram should be rgba(0, 136, 204, 0.55)")
-
-    def test_telegram_after_color_muted(self):
-        """The ::after color rule for telegram uses rgba."""
-        pattern = r'\.session-item\.cli-session\[data-source=["\']telegram["\']\]::after\s*\{[^}]*color:\s*rgba\(0,\s*136,\s*204,\s*0\.55\)'
-        self.assertRegex(STYLE_CSS, pattern,
-            "::after color for telegram should be rgba(0, 136, 204, 0.55)")
-
-
-class TestFormatSourceTagHelper(unittest.TestCase):
-
-    def test_format_source_tag_helper_exists(self):
-        """_formatSourceTag function must be defined in sessions.js."""
-        self.assertIn("function _formatSourceTag(", SESSIONS_JS,
-            "_formatSourceTag helper function not found in sessions.js")
-
-    def test_format_source_tag_maps_telegram(self):
-        """_formatSourceTag maps 'telegram' to 'via Telegram'."""
-        self.assertIn("telegram:'via Telegram'", SESSIONS_JS,
-            "sessions.js should map telegram -> 'via Telegram'")
-
-    def test_format_source_tag_maps_discord(self):
-        """_formatSourceTag maps 'discord' to 'via Discord'."""
-        self.assertIn("discord:'via Discord'", SESSIONS_JS,
-            "sessions.js should map discord -> 'via Discord'")
-
-    def test_format_source_tag_maps_slack(self):
-        """_formatSourceTag maps 'slack' to 'via Slack'."""
-        self.assertIn("slack:'via Slack'", SESSIONS_JS,
-            "sessions.js should map slack -> 'via Slack'")
-
-    def test_metabits_uses_format_helper(self):
-        """The metaBits push for source_tag should use _formatSourceTag with a null guard."""
-        # Fix #429: the push now uses a temp variable guard to suppress null/N/A results:
-        #   const _stLabel=_formatSourceTag(s.source_tag); if(_stLabel) metaBits.push(_stLabel)
-        # The old direct push pattern is gone; verify the guarded pattern is present.
-        self.assertIn("_formatSourceTag(s.source_tag)", SESSIONS_JS,
-            "metaBits push should still use _formatSourceTag() for source_tag display")
-        self.assertIn("metaBits.push(_stLabel)", SESSIONS_JS,
-            "metaBits push should use guarded _stLabel variable (fix #429)")
-
-    def test_raw_source_tag_not_pushed_directly(self):
-        """The old raw metaBits.push(s.source_tag) should not exist."""
-        self.assertNotIn("metaBits.push(s.source_tag)", SESSIONS_JS,
-            "Raw s.source_tag should not be pushed directly to metaBits")
-
-
 if __name__ == "__main__":
     unittest.main()