[STORY] v4-S29: Add deprecation warnings for removed Gradle commands

[raifdmueller]

User Story

As a documentation author, I want helpful error messages when I use v3-era Gradle commands.

Acceptance Criteria

Scenario: User runs ./gradlew
  Given a v4 installation without Gradle
  When a user runs ./gradlew generateHTML
  Then the error message says: "Gradle is no longer used in v4. Use: ./dtcw generateHTML"

Scenario: User runs dtcw with Gradle-style task group
  When a user runs ./dtcw tasks --group doctoolchain
  Then the output lists available tasks
  And a note says: "v4 uses direct script invocation. --group is ignored."

Priority: Should

Epic: v4-E5 (#7)

Blocked by: v4-S3

[raifdmueller]

Analysis

Migration Guide Structure

1. What changed — Gradle removed, core module dissolved, jBake replaced (1 page)
2. What you need to do — Usually nothing (config is compatible). If you used ./gradlew directly, switch to ./dtcw. (half page)
3. New requirements — AsciiDoctor must be installed (auto-installed by dtcw) (half page)
4. Custom task migration — If you had custom Gradle tasks, convert to Groovy scripts (1 page with example)
5. FAQ — Common error messages and solutions (1 page)

Format: AsciiDoc, published as part of the microsite

🤖 Generated with Claude Code

[raifdmueller]

Analysis (S29: Deprecation Warnings)

Deprecation Messages Needed

1. ./gradlew <task> → "Gradle is no longer used in v4. Use: ./dtcw "
2. ./dtcw tasks --group doctoolchain → list tasks, note that --group is ignored
3. References to core/ module in error messages → update to script locations

Implementation

Add a check in dtcw: if user runs ./gradlew, print migration hint.

Estimated: ~20 LOC in dtcw

🤖 Generated with Claude Code