telegram-mcp MCP server

### Extraction

- Optional local PDF/DOCX text extraction through `telegram-context-mcp[extraction]`. `extract_attachment_text` reads one selected attachment and returns bounded Unicode text slices with source digests and physical PDF page references. Temporary results expire after 15 minutes and recheck source access and media identity on every read.
- Document parsing runs in a terminable subprocess with explicit input, page, text, expansion and time limits. Unsupported, encrypted, damaged and textless documents have distinct errors; DOCX body-only omissions and PDF pages without text are reported. `get_status` advertises availability without requiring the extra for ordinary tools.
- Recover structurally damaged PDFs with one bounded tolerant retry, reported as `DOCUMENT_RECOVERED`; accept PDF signatures within the first 1024 bytes and preserve original source digests and page provenance. Resolve DOCX main parts through OPC relationships and report macro-enabled DOCM as unsupported.
- Cap each expanded DOCX entry at 32 MiB and Linux worker address space at 1 GiB (or a stricter inherited limit). Allocation failures report `EXTRACTION_LIMIT_EXCEEDED`; Windows/macOS retain the existing time and document budgets without an OS memory cap.
- Avoid a redundant source request between attachment download and parsing while retaining fresh permission and attachment checks before delivery and on continuation.

### Authentication

- `telegram-mcp login --qr` displays a terminal QR for approval in the Telegram phone app, with optional 2FA and up to three expiring codes per invocation. It reuses the configured session, keeps the existing phone/code flow, and requires no external QR executable. Cancellation and failures release the session; rate limits report the wait without sleeping. Tokens and raw authorization responses are not printed.

### Distribution

- Optional Linux systemd user unit and installation/lifecycle guide for the shared HTTP server. It runs a persistent installed executable, restarts after crashes, and preserves the existing local authentication and session ownership model. The unit works with published 0.5.1; no package upgrade is required to adopt it.
- Preview Claude Desktop MCPB packaging with a shared-server `connect` launcher, external configuration-file selection, the matching release wheel and locked runtime dependencies. CI checks reproducible archives and isolated launches on Linux, Windows and macOS; GitHub releases include the bundle and SHA-256 separately from the PyPI artifacts. Initial Windows Desktop connection and catalog checks passed on Windows 11 25H2 with Claude Desktop 4.29.0. Additional Desktop UI/lifecycle scenarios and macOS Desktop remain manually unverified. See the [bundle guide](https://github.com/egor-fedorov/telegram-mcp/blob/main/docs/mcpb.md).

### Agent Skill

- Add an optional MIT-licensed `telegram-mcp` Agent Skill for source-linked reading, bounded digests, watch acknowledgement and selected attachments, with client installation instructions. It uses existing MCP tools and does not change server permissions or install automatically with the Python package.

### Dependencies

- Refresh the locked HTTP/SSE and TLS dependencies, including Starlette 1.10.0, sse-starlette 3.6.0, cryptography 50.0.2 and truststore 0.10.5, with supporting parser, IDNA and test-plugin updates. Dependency constraints and MCP contracts are unchanged.
- Update pytest-asyncio to 1.4.1 and group its test stack's `iniconfig` and `pluggy` updates with development tools in Dependabot.

### Upgrade and validation

- Upgrade the shared server and client proxies to 0.6.0, restart the server and refresh client tools. Existing sessions, permissions, checkpoints and subscriptions remain compatible; no state migration is required.
- For PDF/DOCX support, install or update the session-owning server with `uv tool install --python 3.12 'telegram-context-mcp[extraction]==0.6.0'` and enable `allow_attachment_downloads`. The ext