Make derivable reduction parameters exact

[isPANN]

Several reductions marked target parameters unavailable even though their constructed values have exact formulas in registered source parameters. This PR adds 24 such formulas across 22 rules. For example, ExactCoverBy3Sets → ILP now reports num_nonzeros = 4 * num_subsets. HamiltonianPath → ILP reports all three ILP sizes exactly, including the empty-graph case, using a source parameter for consecutive positions. BMF → BicliqueCover no longer claims an exact edge count from matrix dimensions alone.

One registry-wide test checks every declared formula field against a constructed target: equality for exact, and predicted ≥ measured for upper_bound. It uses canonical examples or registered generators where examples are unavailable. Turing Decision wrappers and two proof-only rules have test-only target constructions because they have no single-shot reduction callback. This check caught a false QUBO → SpinGlass exact claim: sparse QUBOs do not have num_vars² interactions. QUBO now exposes its natural nonzero quadratic-term count, which restores an exact interaction formula and also makes all three QUBO → ILP size formulas exact. The canonical instructions and add-rule guide now require coverage for every formula field in future rules.

Validation: make check passed (formatting, Clippy, workspace tests, and doctests).

[codecov]

Codecov Report

❌ Patch coverage is 98.11143% with 20 lines in your changes missing coverage. Please review.
✅ Project coverage is 96.75%. Comparing base (309ac65) to head (f743491).

Files with missing lines	Patch %	Lines
src/unit_tests/parameter_formula_validation.rs	90.45%	19 Missing ⚠️
src/rules/multiplechoicebranching_ilp.rs	90.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1174      +/-   ##
==========================================
+ Coverage   96.73%   96.75%   +0.02%     
==========================================
  Files        1069     1070       +1     
  Lines      138549   139440     +891     
==========================================
+ Hits       134023   134914     +891     
  Misses       4526     4526              

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.