feat(deps): Add uv ecosystem to Dependabot configuration

[WilliamBerryiii]

Summary

Dependabot is configured for npm and GitHub Actions ecosystems but has no uv ecosystem entry. Python dependencies in pyproject.toml / uv.lock files will not receive automated security update PRs until uv is added to the Dependabot configuration.

Context

PR #868 introduces the first Python skill with dependencies managed via uv and pyproject.toml. Dependabot now supports uv as a native package ecosystem, understanding pyproject.toml and uv.lock directly. This avoids the impedance mismatch of using the pip ecosystem to manage uv-locked dependencies.

The existing .github/dependabot.yml follows a pattern of one entry per ecosystem with directory targeting. Each Python skill directory requires its own entry because Dependabot does not support glob patterns in the directory field.

Architecture: Multi-Skill Scaling

With independent Python projects (one pyproject.toml per skill), each skill directory needs a separate Dependabot entry. This is a one-time step per skill and should be part of the "new Python skill" checklist.

Example configuration for multiple skills:

- package-ecosystem: "uv"
  directory: "/.github/skills/experimental/powerpoint"
  schedule:
    interval: "weekly"
    day: "monday"

- package-ecosystem: "uv"
  directory: "/.github/skills/shared/data-processor"
  schedule:
    interval: "weekly"
    day: "monday"

Changes Required

File	Change
.github/dependabot.yml	Add uv ecosystem entry for each Python skill directory

Initial entry for the PowerPoint skill:

- package-ecosystem: "uv"
  directory: "/.github/skills/experimental/powerpoint"
  schedule:
    interval: "weekly"
    day: "monday"

Acceptance Criteria

• .github/dependabot.yml includes a uv ecosystem entry for the PowerPoint skill directory
• Dependabot recognizes the pyproject.toml and uv.lock in the targeted directory
• Existing npm and GitHub Actions Dependabot entries remain unaffected
• Dependabot dashboard shows the uv ecosystem as active
• Future Python skills are added as separate uv ecosystem entries (no glob support exists)

Dependencies

None. This is a standalone configuration change.

Related

• PR feat(skills): add PowerPoint automation skill with YAML-driven deck generation #868 — PowerPoint automation skill (first Python skill)
• feat(ci): Add Python file extensions to copyright/SPDX header validation #883 — Copyright/SPDX header validation for Python
• feat(ci): Add Python to CodeQL analysis language matrix #884 — CodeQL Python integration
• feat(skills): Mandate unit testing, extend CI coverage, and document language support process #634 — Prior CI coverage expansion work (closed)