[REPORT] Add student-facing example report templates

[allnes]

What changed

• Converted the existing tasks/example report tree into student-facing report templates.
• Added root guidance for the report tree, shared files, implementation sections, formulas, appendix, and filling rules.
• Added thread-semester report sections for problem statement, algorithm description, build/run instructions, correctness verification, experiment setup, performance results, analysis, and conclusion.
• Added process-semester report sections for T1, T2, and T3 with separate sequential and MPI baselines.
• Added implementation-specific report templates for sequential, MPI, OpenMP, oneTBB, STL/std::thread, and combined implementations.
• Kept all changes inside existing Markdown files under tasks/example.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.42%. Comparing base (b5700c2) to head (fd86a9f).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #792   +/-   ##
=======================================
  Coverage   92.42%   92.42%           
=======================================
  Files          15       15           
  Lines         515      515           
  Branches      199      199           
=======================================
  Hits          476      476           
  Misses          4        4           
  Partials       35       35           

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[aobolensk]

Does report really need to be that verbose in general? And I still not fully get the multilayer structure of the report itself. Is that really needed?

[allnes]

Does report really need to be that verbose in general? And I still not fully get the multilayer structure of the report itself. Is that really needed?

I ran a few experiments to understand where the agent tends to get stuck, and this structure is based on those results.

If you think it is too heavy or excessive, we can discuss it separately.

But in any case, the agents are already generating this content, so the template is intentionally designed to make the report a bit more demanding and force a more careful output.

[allnes]

And I have a plan convert it to pdf
example-report-template.pdf