chore(quality): define TypeScript test contract

[aaf2tbz]

Summary

Establish the TypeScript/test-contract slice of #919. This PR makes the maintained test surface explicit and introduces the minimum shared TypeScript strictness improvement; it does not close the issue.

Changes

• Replaced the package-script fan-out with a root test command that invokes every maintained test root and excludes vendored references/.
• Added a regression test that locks the root test contract against accidental coverage loss.
• Enabled noUncheckedIndexedAccess in the shared root TypeScript config and fixed the newly surfaced unsafe connector-base indexing.
• Regenerated the committed marketing content index and corrected the contributor documentation to describe the daemon typecheck exception accurately.

Type

• feat — new user-facing feature (bumps minor)
• fix — bug fix
• refactor — restructure without behavior change
• chore — build, deps, config, docs
• perf — performance improvement
• test — test coverage

Packages affected

• @signet/core
• @signet/daemon
• @signet/cli / dashboard
• @signet/sdk
• @signet/connector-*
• @signet/web
• predictor

Screenshots

N/A — developer tooling and test contract only.

PR Readiness (MANDATORY)

• Spec alignment validated (INDEX.md + dependencies.yaml)
• Agent scoping verified on all new/changed data queries
• Input/config validation and bounds checks added
• Error handling and fallback paths tested (no silent swallow)
• Security checks applied to admin/mutation endpoints
• Docs updated for API/spec/status changes
• Regression tests added for each bug fix
• Lint/typecheck/tests pass locally

Migration Notes (if applicable)

N/A — no migrations changed.

• Migration is idempotent
• Daemon Rust parity reviewed or explicitly N/A
• Rollback / compatibility note included in PR description

Testing

• bun test passes
• bun run typecheck passes
• bunx biome check passes for changed handwritten files
• Tested against running daemon: N/A

Validated:

• bun test scripts/test-contract.test.ts tests/integration/web-content-index-regression.test.ts libs/connector-base/index.test.ts
• bun run --filter '@signet/core' build
• npx tsc -p platform/core/tsconfig.json --noEmit
• npx tsc -p libs/connector-base/tsconfig.json --noEmit --noUncheckedIndexedAccess
• git diff --check

AI disclosure

• AI tools were used (see assisted work in this session)

Follow-ups

The full maintained-suite command deliberately exposes remaining baseline debt: Rust route-parity artifacts and native SQLite-extension coverage. PR 3 owns the Rust baseline; PR 4 makes the now-defined checks mandatory in CI and branch protection. The daemon typecheck remains non-blocking until #969 is resolved.