Add open source alternative to Taplio: SDP (Social Daily Poster)

Following the "Adding an Open Source Alternative to Existing Proprietary Tool" template in CONTRIBUTING_TO_OSB.md.

Add open source alternative to Taplio:

- **Name**: SDP (Social Daily Poster)
- **Repository**: https://github.com/dimamak/sdp
- **Description**: Self-hosted daily social poster. It reads your Claude Code or Codex session transcripts, screenshots and messages at the end of the day, drafts a LinkedIn or X post from what you actually did, and sends it to a private Telegram bot for approval before anything publishes.
- **Similarity Score**: 60
- **Notes**: Taplio is a hosted LinkedIn growth tool: AI post generation, scheduling, analytics, lead search. SDP overlaps on the part most people actually use it for, which is getting a post written and out of the door, and differs in where the material comes from. Taplio starts from a prompt or a template; SDP starts from the work you already did that day, harvested from coding-agent sessions, screenshots and optionally Telegram, Gmail and WhatsApp.

Honest scoping of the 60: SDP has no analytics, no lead search, no content calendar and no team features. What it does have that Taplio does not: everything runs on your own machine, posting goes through the official LinkedIn and X APIs, and nothing publishes without an explicit approval tap in Telegram.

Python 3.10+, MIT, no server required. Windows, macOS and Linux, with CI on all three.

Also a reasonable partial alternative to Hypefury and Typefully for the same reason, though Taplio is the closest fit.

Disclosure: I maintain the project.

Start by reading CONTRIBUTING_TO_OSB.md to follow the repository's process for adding an alternative, then locate the catalog entry or data file used by the project. Add SDP with the repository, description, similarity score, notes, and disclosure details from this issue, and verify that the entry renders correctly in the project.

Written by the indexing model from the issue text.