typescript: accept contextual function names

[PerishCode]

Why

TypeScript function declarations can legally use contextual accessor words such
as get as ordinary function names. The parser previously treated get only as
an accessor keyword in this position, so valid wrapper std helpers like
function get(name: string, fallback = ""): string { ... } produced parse
errors.

Refs #51.

What

• Allow get and set as contextual names in TypeScript function
  declarations.
• Add parser coverage for a function get(...) declaration followed by an
  exported object shorthand reference.

Tests

• cargo fmt --all --check
• cargo test --locked -p flavor-plugin-typescript
• cargo clippy --locked --workspace --all-targets -- -D warnings
• cargo test --locked --workspace
• cargo run --locked -p flavor-cli -- check --root . --config flavor.toml
• Published beta v0.3.5-beta.1 from this branch:
  https://github.com/PerishCode/flavor/actions/runs/28160836591
• Updated local CLI to flavor v0.3.5-beta.1
• Verified the reporter scenario in PerishCode/runseal
feat/deno-tool-surface-slim with:
  • flavor check --root . --config flavor.toml
  • deno check --config .runseal/deno.json --lock deno.lock --frozen=true ...