feat: Ingress reCAPTCHA bot - initial public release

Telegram group verification bot with image recognition challenge.
New members must identify Ingress game items from composed images
before gaining chat permissions.

Features:
- Image-based CAPTCHA with configurable challenge parameters
- Multi-language support (zh/en) with per-user language preference
- Inline keyboard verification with bilingual labels
- Cross-session failure tracking (kick on 1st fail, ban on 2nd)
- Anti-spam rejoin cooldown
- Admin management via bot commands
- Docker deployment with SQLite persistence

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: ChestnutLUO

.env.example

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+# Telegram Bot Token (required)
+# 从 @BotFather 获取
+TELEGRAM_BOT_TOKEN=your_bot_token_here
+
+# Bot 管理员 User ID 列表 (逗号分隔)
+# 使用 /myid 命令获取你的 User ID
+# 示例: BOT_ADMIN_IDS=123456789,987654321
+BOT_ADMIN_IDS=
+
+# Database path
+DATABASE_PATH=/data/bot.db
+
+# Image cache path
+IMAGE_CACHE_PATH=/images
+
+# Verification parameters
+VERIFY_IMAGE_COUNT=3          # 验证时显示的图片数量
+VERIFY_REQUIRED_CORRECT=2     # 需要答对的数量
+VERIFY_TIMEOUT_SECONDS=120    # 验证超时时间（秒）
+VERIFY_MAX_RETRY=1            # 最大重试次数
+VERIFY_DISTRACTOR_COUNT=3     # 干扰选项数量（总选项 = 图片数量 + 干扰数量）
+
+# Anti-spam: cooldown in seconds for users who rejoin
+REJOIN_COOLDOWN_SECONDS=300   # 重新加入冷却时间（秒）

.gitignore

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+# Data files
+/data/
+/images/
+
+# Environment files
+.env
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Go
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+*.test
+*.out
+go.work
+
+# Build
+/bot
+
+# Claude Code local settings
+.claude/

Dockerfile

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+# Build stage
+FROM golang:1.21-alpine AS builder
+
+# Install build dependencies
+RUN apk add --no-cache gcc musl-dev sqlite-dev
+
+WORKDIR /app
+
+# Copy go mod files
+COPY go.mod go.sum ./
+RUN go mod download
+
+# Copy source code
+COPY . .
+
+# Build with CGO enabled for SQLite
+RUN CGO_ENABLED=1 GOOS=linux go build -a -ldflags '-linkmode external -extldflags "-static"' -o bot ./cmd/bot
+
+# Runtime stage
+FROM alpine:3.19
+
+# Install runtime dependencies
+RUN apk add --no-cache \
+    ca-certificates \
+    tzdata \
+    sqlite-libs \
+    ttf-dejavu
+
+# Set timezone
+ENV TZ=Asia/Shanghai
+
+WORKDIR /app
+
+# Copy binary from builder
+COPY --from=builder /app/bot .
+
+# Create directories for volumes
+RUN mkdir -p /data /images
+
+# Run as non-root user
+RUN adduser -D -u 1000 botuser
+RUN chown -R botuser:botuser /app /data /images
+USER botuser
+
+CMD ["./bot"]