Task: Implement SEO-friendly URLs for projects, tasks, and worklogs

It is necessary to implement stable, human-readable URIs for three types of entities on fi1osof.ru:

• projects;
• tasks;
• worklogs.

Currently, links to these entities are tied to IDs. A separate uri field with SEO-friendly URLs and server-side link existence validation is already used for concepts; a similar principle is needed for working entities.

Minimum requirements:

1. Add a separate uri field or equivalent stable slug/route for Project, Task, and Worklog.
2. Generate human-readable URLs from the entity name/title with a uniqueness guarantee.
3. Do not break existing ID routes: old links must continue to work or correctly redirect to the canonical URI.
4. Use human-readable URLs as the canonical path in internal Markdown links and the interface.
5. Handle entity renaming: the URI should not spontaneously break existing links; a clear stability or redirection strategy is needed.
6. Add server-side validation of internal links, similar to concepts, so that non-existent routes are not saved as valid links.
7. After implementation, update the rules/skill for working with fi1osof.ru: before generating internal links, the agent must read the actual entity uri rather than constructing the path from the ID or name.

The goal is to unify projects, tasks, concepts, and worklogs under a single system of stable internal cross-linking.