Add Powershell install script

[X1nto]

Goal

This adds a Powershell install script for Windows users. The script is a one-to-one port of the bash version, except for the fact that it uses directory junctions instead of symlinks. Functionally, they're the same for this usecase. Symlinks in Windows require privilege escalation or developer mode to be enabled, directory junctions don't.

Affected files

• Skill(s): scripts/install-skills.ps1, README.md
• Reference doc(s): Irrelevant
• Index / README / SPEC / CORPUS: None.

Type of change

• New skill
• Fix or update to an existing skill
• New references/ doc
• INDEX.md update (symptom row, API row, or workflow-phase entry)
• README.md / SPEC.md / CORPUS.md update
• Tooling or .github config

Authoritative sources cited

List the primary sources the new or updated content is grounded in. Every API claim must point to one of:

• Android Developers documentation
• AndroidX source on cs.android.com (pinned to a path)
• Compose Compiler source
• Compose / AndroidX release notes
• Posts by Ben Trengrove, Chris Banes, Manuel Vivo, or skydoves writing on ProAndroidDev / GetStream blog

Irrelevant

SPEC.md self-check

Run through docs/SPEC.md §9 before requesting review. All items below must pass for any skill body that changes:

• Frontmatter name matches the folder slug
• Frontmatter description is third person, ≤1024 chars, names ≥3 trigger vocabulary variants, and closes with a "use when the developer mentions X" hammer
• Frontmatter contains license: Apache-2.0. See LICENSE for complete terms. exactly
• metadata.author is Jaewoong Eum (skydoves) and metadata.keywords has ≥4 entries including jetpack-compose and performance
• No reserved words anthropic or claude appear in the skill name
• Body is ≤500 lines; longer material moved to references/
• At least one RIGHT / WRONG paired snippet (for any skill that teaches a code transform), with // WRONG because: … rationale on the WRONG block
• Mandatory rules use MUST, MUST NOT, DO NOT, or PREFERRED in bold caps
• Verification section is a checkbox list of provable checks
• References section has ≥3 authoritative URLs
• No first person, no emojis, no time-sensitive phrasing

Cross-reference updates

• INDEX.md updated under every lookup section the skill belongs to (By symptom, By API, By workflow phase)
• README.md skill-categories bullet updated if the change introduces or renames a topic in that category
• Sibling skills' "When NOT to use" / "References" sections cross-link to this change where relevant

Verification

Describe how the workflow in the SKILL.md was exercised. For code-level skills, paste output from running the verification checklist on a sample project: compiler reports, Layout Inspector counts, Perfetto trace section names, or ./gradlew :app:assembleRelease output.

Irrelevant

Code review

All submissions require review. Use GitHub pull requests for this purpose. See GitHub Help for more information.