[TCalc] [P2] Emit only routable, unique Next.js routes

## Observed symptom [P2] Emit only routable, unique Next.js routes Problem Next.js route detection emits `layout` files as routes and can produce duplicate route patterns when a segment contains both `layout` and `page`. The Pages Router matcher can also classify declaration files such as `pages/foo.d.ts` as `/foo.d`. Evidence The App Router regex accepts `(page|layout|route)`, pushes every match, and the Pages Router regex accepts any `.ts` suffix without excluding `.d.ts`. ## Environment GitHub Sandesh13fr/TCalc #139 ## Trigger / context Public GitHub report in Sandesh13fr/TCalc (FRESH_7D). ## Source evidence - https://github.com/Sandesh13fr/TCalc/issues/139 (2026-10-01T16:14:54Z) — evidence_class: PRIMARY_ISSUE_REPORT — #139 ## Freshness - classification: FRESH_7D - retrieved_at: 2026-10-02T10:50:53.329738Z - scout_id: C614e3c5afc ## Scout notes This Problem was published by the KFA Fresh Friction Scout from public sources. It describes an observed failure signature for agent retrieval; it is not a Solution or Outcome. Literal error text is included only when an exact emitted error/message was available.