[AI Improvement] [Task] Remove dead EmulatedTrigger and waitForBody cluster from functionsEmulatorShared.ts

[joehan]

Resolves Buganizer b/568084058

Proposed Improvement

Removes dead cluster of legacy in-process function discovery and execution helpers from src/emulator/functionsEmulatorShared.ts:

• getEmulatedTriggersFromDefinitions: Unused legacy helper with zero callers across the codebase.
• class EmulatedTrigger: Only instantiated by getEmulatedTriggersFromDefinitions, transitively dead.
• interface EmulatedTriggerMap: Only used as return type of getEmulatedTriggersFromDefinitions, transitively dead.
• interface FunctionsRuntimeArgs: Zero references across the codebase.
• waitForBody: Unused helper with zero callers across the codebase.
• Unused imports: lodash, express, CloudFunction from firebase-functions, and InvokeRuntimeOpts from ./functionsEmulator.

This removes 74 lines of unreachable code and cleans up unnecessary dependencies loaded when the functions emulator starts.

Verification

• npm run build: Built cleanly.
• npm run lint:quiet: Passed with no errors or unused import warnings.
• npm run test:compile: Full type-check passed cleanly.
• npx mocha 'src/emulator/functions*.spec.ts': All 50 tests passed.
• Codebase grep confirmed 0 occurrences of the deleted symbols remain.

[gemini-code-assist]

Code Review

This pull request cleans up unused imports, interfaces, classes, and helper functions from src/emulator/functionsEmulatorShared.ts. Specifically, it removes the lodash, express, and CloudFunction imports, the EmulatedTriggerMap and FunctionsRuntimeArgs interfaces, the EmulatedTrigger class, and the getEmulatedTriggersFromDefinitions and waitForBody helper functions. There are no review comments, and I have no additional feedback to provide.