Add KattisScraper and USACOScraper with contest list, metadata, and
test case fetching. Register kattis and usaco in PLATFORMS,
PLATFORM_DISPLAY_NAMES, and default platform configs.
Problem: the hooks API conflated distinct lifecycle scopes under a flat
table with inconsistent naming (setup_code, before_run, setup_io_input),
making it hard to reason about when each hook fires.
Solution: introduce two namespaces — hooks.setup.{contest,code,io} for
one-time initialization and hooks.on.{enter,run,debug} for recurring
events. hooks.setup.contest fires once when a contest dir is newly
created; hooks.on.enter is registered as a buffer-scoped BufEnter
autocmd and fires immediately after setup.code. The provisional buffer
setup_code callsite is removed as it ran on an unresolved temp buffer.
Problem: after apply_template writes a file's content to the buffer,
cursor positioning was left entirely to the user's setup_code hook,
forcing everyone to reimplement the same placeholder-stripping logic.
Solution: add an optional templates.cursor_marker config key. When set,
apply_template scans the written lines for the marker, strips it, and
positions the cursor there via bufwinid so it works in both the
provisional and existing-file paths.
Problem: CpPlatformOverrides lacked a template field and merge_lang()
never copied ov.template into the effective language config, so
per-platform template overrides were silently dropped.
Solution: add template? to CpPlatformOverrides and forward it in
merge_lang(), matching how extension is handled.
Problem: output comparison used exact string equality after whitespace
normalisation, causing correct solutions to fail on problems where
floating-point answers are accepted within a tolerance (e.g. 1e-6).
Solution: add an optional ui.panel.epsilon config value. When set,
actual and expected output are compared token-by-token: numeric tokens
are compared with math.abs(a - b) <= epsilon, non-numeric tokens fall
back to exact string equality. Per-problem epsilon can also be stored
in the cache and takes precedence over the global default.
Problem: new solution files were always created empty, requiring users
to manually paste boilerplate or rely on editor snippets that fire
outside cp.nvim's control.
Solution: add an optional template field to the language config. When
set to a file path, its contents are written into every newly created
solution buffer before the setup_code hook runs. Existing files are
never overwritten.
Problem: tbl_deep_extend merges user platforms on top of defaults, so
all four default platforms survive even when the user only configures a
subset. The picker then shows platforms the user never intended to use.
Solution: before the deep merge, prune any default platform not present
in the user's platforms table. This preserves per-platform default
filling (the user doesn't have to re-specify every field) while ensuring
only explicitly configured platforms appear.
