Update Docker images to Debian trixie (Python 3.13-slim-trixie)

[Erwin Kersten (erwinkersten)]

Moves both Dockerfiles from python:3.13-slim-bullseye to python:3.13-slim-trixie, plus two small fixes surfaced by the upgrade.

Fixes: #2420

Changes

• Dockerfile, packages/markitdown-mcp/Dockerfile: base image to python:3.13-slim-trixie.
• exiftool package name: exiftool does not exist in trixie (apt-cache policy exiftool → Candidate: (none)), so the build fails at apt-get install. Switched to libimage-exiftool-perl, which provides /usr/bin/exiftool and matches the existing EXIFTOOL_PATH.
• ORT_DISABLE_TELEMETRY=1: onnxruntime (via magika) logs Failed to persist telemetry device ID on every run, because the images run as nobody, whose $HOME is /nonexistent. Setting this removes the noise — relevant for the MCP server, where stray stderr output clutters client logs.
• packages/markitdown-mcp/src/markitdown_mcp/__main__.py: call Settings.model_rebuild() before FastMCP("markitdown") is constructed, to silence IncompleteFieldDefinitionWarning: Field 'lifespan' has an incomplete definition from newer pydantic-settings. This resolves the forward reference rather than suppressing the warning: Settings.model_fields['lifespan'].annotation goes from an unresolved string to a real Callable[[FastMCP], AbstractAsyncContextManager[LifespanResultT]] | None. The call must precede first instantiation, since that is when the warning fires.

Verification

Both images build and run:

• exiftool 13.25 and ffmpeg 7.1.5-0+deb13u1 resolve at the paths EXIFTOOL_PATH / FFMPEG_PATH point to.
• markitdown CLI converts HTML → Markdown correctly.
• markitdown-mcp completes a full stdio JSON-RPC handshake, tools/list, and a real tools/call conversion. stderr now contains only the normal MCP request log line, no warnings.

[Copilot]

🟢 Approval recommended

The focused compatibility updates are internally consistent and address the reported build and runtime issues.

Pull request overview

Updates Docker images to supported Debian Trixie and resolves upgrade-related runtime warnings.

Changes:

• Upgrades both images to python:3.13-slim-trixie.
• Replaces the unavailable exiftool package and disables ONNX telemetry.
• Rebuilds MCP settings before server initialization.

File summaries

File	Description
Dockerfile	Updates the primary image and runtime dependencies.
packages/markitdown-mcp/Dockerfile	Updates and streamlines the MCP image.
packages/markitdown-mcp/src/markitdown_mcp/__main__.py	Resolves the MCP settings forward reference.

Review details

• Files reviewed: 3/3 changed files
• Comments generated: 0
• Review effort level: Balanced

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