Add symmetrization conventions report

[mmikhasenko]

Summary

• add a standalone Quarto report on permutation, charge-conjugation, and symmetrization conventions
• document explicit recipes and cross-checks for identical-particle amplitude models
• include worked notes for three-pion, Xi_b -> p K K, J/psi -> eta p pbar, B_s -> J/psi p pbar, and chi_c -> K K pi pi cases
• include a technical appendix, convention ledger, references, and report styling

Motivation

Amplitude models with identical particles need explicit, auditable conventions
for label permutations, exchange phases, charge conjugation, and coherent sums.
This report collects those conventions and their case-by-case checks in one
renderable reference.

Validation

• rendered all 13 report pages with quarto render symmetry_report
• confirmed the generated report entry point is symmetry_report/_report/index.html
• confirmed the branch contains no pp -> pp K+ K- tutorial changes

[gemini-code-assist]

Code Review

This pull request adds pre-rendered static examples and a comprehensive Quarto-based report on discrete symmetries in cascade decays to the documentation. It introduces a new amplitude model example for $pp \to p_1 p_2 K^+ K^-$ along with its Julia environment, Quarto notebook, and Markdown files, and updates the documentation build script to copy these static examples. The review feedback recommends using force = true when copying assets in the build script to prevent transient failures, adding [compat] bounds for all dependencies in the examples environment to ensure reproducibility, and using explicit multiplication instead of implicit multiplication in the example code.

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[gemini-code-assist]

Using force = true when copying directories in build scripts is a safer defensive programming practice to prevent transient build failures if the destination directory already exists or was not fully cleaned up.

    cp(source_assets, joinpath(dirname(destination), spec.asset_dir); force = true)

[gemini-code-assist]

It is highly recommended to specify [compat] bounds for all dependencies in examples/Project.toml (such as DataFrames, Plots, ThreeBodyDecays, etc.) to ensure long-term reproducibility of the examples and prevent future breaking releases of these packages from breaking the build.

[gemini-code-assist]

Using implicit multiplication like 2particles.proton can be confusing or look like a typo. It is clearer and more idiomatic to write explicit multiplication 2 * particles.proton.

@assert settings.sqrt_s > 2 * particles.proton + 2 * particles.kaon

[gemini-code-assist]

Using implicit multiplication like 2particles.proton can be confusing or look like a typo. It is clearer and more idiomatic to write explicit multiplication 2 * particles.proton.

Suggested change

	@assert settings.sqrt_s > 2particles.proton + 2particles.kaon
	@assert settings.sqrt_s > 2 * particles.proton + 2 * particles.kaon