feat: add interface method receiver chapter

[thomasnormal]

What changed

• Add sv/interface-method-receiver, a runnable lesson for receiver-specific %m paths and parenthesized virtual-interface calls.
• Register the lesson in the metadata, hierarchy, curriculum, receipt matrix, census, and browser QA.
• Record exact-tip Mox ed441eb5b58 native interpreter/compile receipts and Xcelium differential receipts.

Evidence

• npm test -- --run: 18 files / 79 tests passed.
• npm run build: passed; existing Svelte accessibility and duplicate-output warnings remain.
• Native Mox exact-tip build: starter fails as calibrated; solution passes interpreter and compile modes with the zero-interpreter gate.
• refdiff: starter both_fail; solution both_pass; outputs equal.
• Focused Playwright: 1 expected-failure pass because the checked-in WASM predates this Mox landing.

Full receipts: artifacts/tutorial/interface-method-receiver/.