fix: resolve install ERESOLVE on quilt — downgrade typescript ^7.0.2 → ^6.0.3 (#33)

[SuperInstance]

What

Aligns the typescript pin to the @typescript-eslint peer ceiling until typescript-eslint catches up. Closes #33.

Why

@typescript-eslint/eslint-plugin@8.70.1 declares peer typescript@">=4.8.4 <6.1.0". The typescript 7.0.2 bump in #31 satisfies that range on its own — but violates it on the peer side, because the plugin's runtime imports typescript and depends on its API.

Per the Coddy typescript-7 changelog (Sept 2026): TypeScript 7.0 ships no stable JavaScript API. Tools that import the compiler as a library — typescript-eslint (type-aware lint rules), ts-node, Vue/Svelte/Angular template checkers, MDX — keep using TypeScript 6. The TS team expects TS 7.1 to ship a new, different API; until then the supported path is the @typescript/typescript6 npm alias alongside TS 7's tsc.

npm install (no flags) refuses to resolve. Every CI job — test (node 20), test (node 22), lint, security audit — dies at the Install dependencies step, before any code runs.

Fix

Minimal, reversible: pin typescript at ^6.0.3 (the pre-#31 state). Touches only the typescript pin in 6 package.jsons (root + packages/cli, core, mcp, sdk, tui); package-lock.json regenerated.

The TS 7 lane can re-open cleanly with two follow-up moves:

1. Bump @typescript-eslint/eslint-plugin and @typescript-eslint/parser to ^9.x when the typescript-eslint team ships peerDeps aligned to TS 7.
2. Use @typescript/typescript6 as an npm alias for ts-node and the type-aware lint rules, while the build uses TS 7's tsc.

That is a 2-PR lane (eslint pin + alias) — out of scope here.

Verification

Local clone at depth-30 (commit f3fbcbd):

command	result
npm install	232 packages added, 0 ERESOLVE
npm run lint	0 errors, 14 warnings (pre-existing comma-dangle)
npm test	15/15 pass, 0 fail, 0 skip

Out of scope

• publish-rubygems.yml chronic red — pre-merge baseline, not caused by TS 7. Documented in TS7 post-merge health check: ci red on main since the typescript 6.0.3 → 7.0.2 merge (ERESOLVE: @typescript-eslint peer caps typescript <6.1.0) #33, separate lane.
• pages-build — already green throughout both deps: bump typescript from 6.0.3 to 7.0.2 in the major group across 1 directory #31 and seed: fail-closed credential key-scan pre-commit (fleet-hooks, wave 53) #32 merges.

cc: keeper (R57 fallback-aware doctrine applied — restore green, then re-attempt the major when peer lands).