docs: add runnable dicke and measure examples

[happykawayigt]

Description

Adds proper runnable Examples sections to dicke and measure as part of #1886.

Changes

• Promote the existing Dicke state snippets into a rendered Examples section.
• Add a rendered Examples section to measure and correct the state/operator argument order in its projector example.

Validation

• Ran every documented snippet directly against this branch and verified the printed results
• Targeted tests (22 passed)
• ruff check
• ruff format --check
• git diff --check
• GitHub Actions test and style checks passed

A full local MkDocs build was not run because mkdocs is unavailable in the local environment. The repository's Docs Preview check was skipped by its workflow configuration.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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[vprusso]

Thanks @happykawayigt. Verified against the branch: the corrected measure(rho, proj_0) prints 1/3 and measure(rho, proj_1) prints 2/3, matching the documented probabilities. The argument-order swap is a real fix, the signature is measure(state, measurement), so state comes first (the value coincides here only because of the symmetry of this particular example). Moving the example-specific math into the Examples: block is the right structure. Merging.