v0.2.6

Changed

• Emoji policy relaxed: rating tiers (rating:* / issue-rating:*) are now
  the ONLY mandatory-emoji labels (clear low→high gradient); all other
  labels leave emoji to the agent's judgment
• Consistency rule added: within one dimension, either ALL labels carry an
  emoji or NONE do — never a mixed half-emoji dimension
• templates/labels.json baseline now ships plain names (no emoji) —
  bug, P0–P3, status: *, dependencies, security…; impact labels
  were already emoji-free, so every dimension is now consistent
• SKILL.md / LABELS.md / README (en + zh) wording updated to the new policy