Restore standard Clay and contributor tooling

[jamiepratt]

Summary

• restore clojure -M:clay to Clay's standard scicloj.clay.v2.main entry point
• restore the original project-level Clay defaults and author-expansion hook
• remove the vocabulary-specific preview wrapper from shared Civitas source
• remove vocabulary-specific :test-clj and :test-cljs aliases from shared deps.edn

The removed code and aliases supported my personal vocabulary-estimation workflow. Preview and test invocation are now isolated in the owning workflow repository and injected through its configured commands, so Civitas contributors can use Clay and define project tests in their preferred manner. Test sources and runners remain in their vocabulary namespace; the resources/ classpath and global Quarto *.cljc configuration are unchanged.

Model validation

Not applicable. This changes preview tooling only; no scorer, estimand, evidence, threshold, or promotion decision changes.

Software tests

• clj-paren-repair src/civitas/db.clj: no changes needed
• clojure -M:test-clj: 27 tests, 157 assertions, 0 failures/errors
• clojure -M:test-cljs: 14 tests, 57 assertions, 0 failures/errors
• the same suites passed after alias removal through workflow-injected -Sdeps aliases
• clojure -M:clay --help: confirmed the standard Clay CLI entry point
• targeted Clay render of managing_brilliant_but_uneven_minds.clj: passed with namespace Quarto metadata and author expansion intact
• external vocabulary preview against the reverted configuration: live page and linked-page fallback passed; Civitas styling, mobile layout, light/dark themes, and console were verified

Publication checks

• full-site gate selected because clay.edn and deps.edn are shared rendering configuration
• quarto render site: 234/234 pages, exit 0
• existing project warnings remained non-fatal, including the unavailable local jank executable

Shared-path audit

This focused PR intentionally changes four shared Civitas paths:

• clay.edn
• deps.edn
• src/civitas/clay_main.clj
• src/civitas/db.clj

Their intended effects are restoring the standard contributor Clay workflow and removing vocabulary-specific test aliases from shared project configuration.