docs(wiki): add cross-reference and source-code hyperlinks throughout
Link source-file references (src/*.rs, tests/*.rs, regret-games/src/kuhn.rs) to the files on GitHub (blob/tree/main), fixing the wrong src/deep.rs path to src/deep/deep.rs. Add page-to-page cross-reference links wherever a page names a concept documented on another page (Game trait, Trainer, Profile, exploitability, subgames, blueprints, abstraction, deep CFR, rtcfr, reference games), so a reader never has to hunt for the referenced topic. Links use page-slug form with no .md extension and no fragile anchors.
docs(wiki): drop .md extension from internal links
docs(wiki): rewrite pages to follow the wiki style guide; add Getting Started
Apply the wiki AGENTS_README style rules across every page: replace em dashes used as colon/period substitutes, drop mechanical boldface and bold inline-header lists, remove 'X, not Y' negative parallelism, and move act/act_stochastic and other panic conditions into the first paragraph of their section. Add a Getting-Started page with a compiling KuhnPoker walkthrough. Trim Home to a hub and drop the duplicated tour, lead Subgames with Subgame::at, and restructure the Game trait page around a worked example instead of a method-by-method walk.
docs(wiki): add API reference pages and correct subgame constructor semantics
Add Game trait, Training, Profiles, Analytics, Subgames, Abstraction, Deep CFR, Evaluation, and Reference games pages, plus a build/test section on Home. Correct the Subgame::new/DepthLimitedSubgame::new description: they wrap an already-stepped state and take Arc<Profile<G>>, so they do not validate a path; Subgame::at is the Result-returning path builder. Link Reference games from Home and drop filler wording.