Doubt v0.3.1 — Verified one-command Agent Skill install

Verified one-command Agent Skill install

This patch adds the remote-publisher layout required by GitHub CLI 2.90.

gh skill install alsoleg89/doubt doubt

The command was tested end to end against the public repository in a clean
directory. GitHub CLI selected v0.3.1, discovered the four-file Doubt skill,
and installed it with repository/ref tracking metadata.

v0.3.0 added the project-level .github/skills/doubt layout used by GitHub
Copilot inside the repository. Remote gh skill discovery uses
skills/*/SKILL.md; this release adds that publisher layout and makes CI
byte-verify both copies against the canonical portable skill.

All v0.3.0 features remain included:

• Agent Skills vs MCP evidence map
• Five-topic map-vs-memo reader study
• balanced local assignment, anonymous JSON export, and no network submission
• fail-closed analysis until ten complete unique reader sessions
• 12/12 adversarial evidence-contract cases

For CI validation of every *.doubt.json map:

- uses: alsoleg89/doubt@v0.3.1

Full changelog: v0.3.0...v0.3.1