feat: scaffold us-cpa skill

docs/us-cpa.md

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+# us-cpa
+
+`us-cpa` is a Python CLI plus OpenClaw skill wrapper for U.S. federal individual tax work.
+
+## Current Milestone
+
+Milestone 1 provides the initial package, CLI surface, skill wrapper, and test harness. Tax logic, IRS corpus download, case workflows, rendering, and review logic are not implemented yet.
+
+## CLI Surface
+
+```bash
+skills/us-cpa/scripts/us-cpa question --question "What is the standard deduction?" --tax-year 2025
+skills/us-cpa/scripts/us-cpa prepare --tax-year 2025 --case-dir ~/tax-cases/2025-jane-doe
+skills/us-cpa/scripts/us-cpa review --tax-year 2025 --case-dir ~/tax-cases/2025-jane-doe
+skills/us-cpa/scripts/us-cpa fetch-year --tax-year 2025
+skills/us-cpa/scripts/us-cpa extract-docs --tax-year 2025 --case-dir ~/tax-cases/2025-jane-doe
+skills/us-cpa/scripts/us-cpa render-forms --tax-year 2025 --case-dir ~/tax-cases/2025-jane-doe
+skills/us-cpa/scripts/us-cpa export-efile-ready --tax-year 2025 --case-dir ~/tax-cases/2025-jane-doe
+```
+
+## Interaction Model
+
+- `question`
+  - stateless by default
+  - optional case context
+- `prepare`
+  - requires a case directory
+  - if none exists, OpenClaw should ask whether to create one and where
+- `review`
+  - requires a case directory
+  - can operate on an existing or newly-created review case
+
+## Planned Case Layout
+
+```text
+<case-dir>/
+  input/
+  extracted/
+  return/
+  output/
+  reports/
+  issues/
+  sources/
+```
+
+## Output Contract
+
+- JSON by default
+- markdown available with `--format markdown`
+- current milestone responses are scaffold payloads with `status: "not_implemented"`
+
+## Scope Rules
+
+- U.S. federal individual returns only in v1
+- official IRS artifacts are the target output for compiled forms
+- conflicting facts must stop the workflow for user resolution