Support Telegram images through Claude Code #187

Outcome

Telegram images supported by #185 also work when the selected agent backend is Claude Code.

Dependency

• Depends on Support inbound Telegram images through Codex #185.

Constraints

• Use Claude Code's native streaming JSON input for requests containing images.
• Send images as base64 content blocks with the validated media type.
• Keep the existing plain-text invocation for requests without images.
• Support new and resumed Claude sessions.
• Do not expose base64 data in logs, errors, audit events, or process arguments.
• Enforce the shared 6 MiB raw limit before base64 expansion.
• Preserve configured, unattended, evaluator, and session-missing behavior.
• Do not fall back to asking Claude to open an arbitrary local path with tools.

Acceptance criteria

• Claude receives caption text and image content in one user message.
• Image-only requests contain a small text placeholder plus the image block.
• New and resumed sessions support images.
• Text-only requests continue using the existing command and output contract.
• Malformed streaming input and Claude failures return typed backend errors.
• Errors and logs never contain base64 content.
• Runner tests cover JSON construction, media types, session modes, size enforcement, and output parsing.

Checks

cargo test --locked claude
cargo test --locked gateway
cargo fmt --all --check
cargo clippy --locked --all-targets -- -D warnings
cargo build --locked
cargo test --locked

Manually route Telegram to Claude, send a screenshot with a question about a visible detail, then send a second image in the same conversation and confirm session continuity.

Out of scope

• Replacing the Claude CLI adapter with the Claude Agent SDK
• Persisting base64 images
• Slack, iMessage, and outbound images