Strip leading @ from reviewer handles in ship skill

[sebastientaggart]

The ship skill passes DEFAULT_REVIEWERS handles directly to gh pr create --reviewer, but the gh CLI rejects handles with leading @ prefixes (e.g. @sebastientaggart) with:

Could not resolve user with login '@sebastientaggart'

Updated the ship skill template to instruct agents to strip any leading @ from each comma-separated handle before constructing the --reviewer argument. Both @alice and alice now work in config, and @org/team correctly becomes org/team.

Issue #20

[sebastientaggart]

Review Summary

Verdict: APPROVE

Findings

• [NOTE] The instruction tells the agent to "strip any leading @ from each comma-separated handle" but relies on the AI agent interpreting and executing this text correctly at runtime — there is no programmatic enforcement (e.g., a sed or tr command in the template). This is consistent with how the rest of the skill file works (natural-language instructions to the agent), so it is not a defect, but worth noting that a misbehaving agent could still pass through the @ prefix. Acceptable for the current architecture.

No blocking issues found. The change is consistent across the source template (skills/ship.md) and all four generated adapter outputs (.agents/, .claude/, .cursor/, .gemini/). The fix correctly addresses the gh CLI's rejection of @-prefixed handles described in issue #20, and the example (@alice,@org/team becomes alice,org/team) is accurate. Hash footers in generated files were updated as expected by sync.sh.