feat(ts): typecheck requires a tsconfig and type-checks Deno code

[CMaintz]

Summary

Foundry v2 does not make sure a TypeScript project's typecheck actually covers its TypeScript. It also has no answer for Deno code. tech-atlas hit both:

• Its typecheck was astro check with no tsconfig.json. That exits 0 after checking only .astro files with loose defaults. src/lib/*.ts, the tests and scripts/ were never type-checked, and adding a tsconfig exposed 124 errors (build(types): add app/tsconfig.json and fix what it exposes tech-atlas#96).
• Its Supabase Edge Functions (Deno: Deno.serve, Deno.env, _shared/ modules) were not type-checked by anything (fixed in ci: adopt Foundry v2 (gate + security facades, habit-hooks, deno check) tech-atlas#94 with deno check).

Changes

• mise/ts.toml typecheck
  • Fails with a clear message when tsconfig.json is missing. (Plain tsc -b already fails, but only with a cryptic TS5083.) The guard is documented to stay when a framework checker replaces tsc -b, since that is where the silent pass happens.
  • Runs deno check $FOUNDRY_DENO_PATHS when that is set, with deno pinned in [tools]. Both are shown commented out in the template.
  • If git tracks Deno code (supabase/functions/*.ts, deno.json[c]) and FOUNDRY_DENO_PATHS is unset, the verb fails instead of leaving that code unchecked.
• presets/typecheck/tsconfig.json (new): strict and check-only (noEmit). Its include covers src, scripts, tests and root *.ts, with notes on extending a framework's strict preset and on keeping Deno code out.
• foundry-init.sh copies the preset for the ts stack (never clobbering an existing file) and prints a note when supabase/functions exists.
• README / FEATURES: preset row and behaviour.

These are additive. A consumer that copied the old template is unaffected until it re-syncs. The gate.yml facade needs no change: mise-action installs deno from [tools], and the verb runs as before.

Verification

I ran the new typecheck script (extracted from mise/ts.toml, Git Bash) in a scratch repo:

Case	Result
tsconfig present, tracked supabase/functions/f/index.ts, FOUNDRY_DENO_PATHS unset	exit 1, message names the file
same, FOUNDRY_DENO_PATHS=supabase/functions	Check supabase/functions/f/index.ts, exit 0
no tsconfig	exit 1, message points at the preset
no Deno code	exit 0

The preset with a type error in src/ makes tsc -b exit 1, and exit 0 once the error is fixed.

Not changed here: tsc -b writes tsconfig.tsbuildinfo even with noEmit. That was already the template's behaviour; consumers may want it in .gitignore.