Fix PM skill auto-complete flakiness under auto directive#

Problem#

The product-manager skill intermittently signals BLOCKED:PERSISTENT for well-defined issues when running under the auto directive, blocking the pipeline unnecessarily.

Task / Link#

Closes #483

Changes#

• SKILL.md Step 6: adds directive-aware completeness gate — classifies issues as "well-specified" when DIRECTIVE=auto and both a problem statement and acceptance criteria are present; skips question-asking for those
• SKILL.md Step 8: adds DIRECTIVE=auto branches — auto-complete path for well-specified issues, 1-round-max path for genuinely ambiguous issues, and explicit note never to signal BLOCKED:PERSISTENT for well-specified issues
• role.md: adds Do rule to auto-complete well-specified issues under auto directive; adds Do Not rules prohibiting clarifying questions and BLOCKED:PERSISTENT signals for well-specified issues under auto

Notes#

• careful directive behavior is unchanged — existing question-asking logic (up to 3 rounds) is preserved
• Genuinely ambiguous issues (empty body, no problem statement) still trigger questions even under auto, but capped at 1 round before forcing finalization
• Prompt changes are non-deterministic; strong directive language (MUST, NEVER) is used to reduce flakiness

Testing#

• Verified modified prompt text confirms auto directive triggers auto-completion for well-specified issues
• Verified careful directive path is unchanged
• No TS/JS code modified — lint/test not applicable