Add Telegram Bot API update workflow

[IRus]

Summary

• add a repository-scoped update-telegram-bot-api skill with guarded source capture, spec review, code generation, stale-file review, and test guidance
• expose :core-gen:parseTelegramBotApi and :core-gen:generateTelegramBotApi as headless Gradle tasks using the BellSoft Java 25 toolchain
• keep one canonical workflow under .agents/skills with a minimal Claude Code loader under .claude/skills
• normalize the generated RichText value properties so regeneration is idempotent

Why

Telegram Bot API upgrades previously depended on IntelliJ run configurations and maintainer knowledge. The new workflow makes the process executable by coding agents while protecting dirty outputs, validating downloaded page source, reviewing untracked and stale generated files, and stopping before publication.

Impact

Codex can invoke $update-telegram-bot-api; Claude Code can invoke /update-telegram-bot-api. The skill covers code generation and verification only—publishing remains a separate workflow.

Validation

• ./gradlew :core-gen:parseTelegramBotApi :core-gen:generateTelegramBotApi
• both skill entrypoints passed quick_validate.py
• repeated code generation produced no additional diff
• ./gradlew --no-daemon -Pkotlin.compiler.execution.strategy=in-process -Dorg.gradle.jvmargs='-Xmx2g -XX:MaxMetaspaceSize=1g -Dfile.encoding=UTF-8' check
• git diff --check origin/main...HEAD