CI paths: TS Typecheck — add self-trigger path and tsconfig.build.json #846

Part of #834. Phase 1 (unanchored corrections — no dependency on any other slice).

What

Two defects in ts-typecheck.yml's filter:

1. It does not name its own file (spec row 16).
2. It filters on packages/ts/tsconfig.json only, but packages/ts/tsconfig.build.json also exists and changing it can break the typecheck without triggering it. Spec row 19 says packages/ts/tsconfig*.json.

Exact change

.github/workflows/ts-typecheck.yml — replace the on: block with:

on:
  push:
    branches: [main]
    paths:
      - 'packages/ts/**/*.ts'
      - 'packages/ts/tsconfig*.json'
      - 'packages/ts/package.json'
      - '.github/workflows/ts-typecheck.yml'
  pull_request:
    paths:
      - 'packages/ts/**/*.ts'
      - 'packages/ts/tsconfig*.json'
      - 'packages/ts/package.json'
      - '.github/workflows/ts-typecheck.yml'

Note tsconfig.json → tsconfig*.json in both lists.

Expected checks on this PR

Files touched: .github/workflows/ts-typecheck.yml only.

MUST run

• TS Typecheck

MUST NOT run

• Python Test, TS Test, Rust Test, Plugins Test, Python Lint, Python Typecheck, TS Lint

May still run (not yet filtered)

• Conventions (all 8 lanes), Release Precheck, Release Config Check, Changelog Check

The tsconfig*.json widening is not exercised by this PR's own file list. Optional probe: push a throwaway commit adding a blank line to packages/ts/tsconfig.build.json, confirm TS Typecheck still appears, then drop the commit before merging.

Acceptance

• The PR's check list matches the three groups above exactly
• Mergify Merge Protections green
• Merge, close this issue

Notes

• No changelog fragment, no e2e attestation. Not anchored in .mergify.yml.