refactor: consolidate coercion contracts (#122458)

* refactor: consolidate coercion contracts

Centralize exact string, record, numeric, date, Boolean, argument, and structured-error coercions while preserving call-site semantics.

Migrate canonical-name collisions and deprecated internal SDK bypasses, deleting 55 net production/tooling lines. Expand declaration ownership enforcement to 101 allowed helpers and add a narrow export-completeness audit.

* fix: preserve standalone script coercions

Keep copied Control UI tooling self-contained and retain the trusted release harness module-relative source seam when the harness runs against an old target cwd.

scripts/lib/arg-utils.runtime.d.mts

@@ -0,0 +1,69 @@
+type StringOptions = {
+  allowEmpty?: boolean;
+  allowInline?: boolean;
+  missingValueMessage?: string;
+  rejectShortOptions?: boolean;
+  repeatable?: boolean;
+  transform?: (value: string) => unknown;
+};
+
+type ConsumedFlag<T extends Record<string, unknown>> = {
+  flag?: string;
+  nextIndex: number;
+  repeatable?: boolean;
+  apply(target: T): void;
+};
+
+type FlagSpec<T extends Record<string, unknown>> = {
+  consume(argv: readonly string[], index: number, args: T): ConsumedFlag<T> | null;
+};
+
+type ParseOptions<T extends Record<string, unknown>> = {
+  allowUnknownOptions?: boolean;
+  duplicateOptionMessage?: (flag: string) => string;
+  ignoreDoubleDash?: boolean;
+  onUnhandledArg?: (arg: string, args: T) => "handled" | void;
+};
+
+export type BoundedUnsignedDecimalResult =
+  | { kind: "syntax" }
+  | { kind: "below" }
+  | { kind: "above" }
+  | { kind: "value"; value: number };
+
+export function readFlagValue(args: readonly string[], name: string): string | undefined;
+export function stripLeadingPackageManagerSeparator(argv: string[]): string[];
+export function parseStrictBooleanArg(value: unknown, label: string): boolean;
+export function classifyBoundedUnsignedDecimal(
+  value: unknown,
+  min: number,
+  max: number,
+): BoundedUnsignedDecimalResult;
+export function parsePermissiveBooleanToken(value: unknown): boolean | undefined;
+export function stringFlag<T extends Record<string, unknown>>(
+  flag: string,
+  key: string,
+  options?: StringOptions,
+): FlagSpec<T>;
+export function stringListFlag<T extends Record<string, unknown>>(
+  flag: string,
+  key: string,
+  options?: Omit<StringOptions, "repeatable" | "transform">,
+): FlagSpec<T>;
+export function intFlag<T extends Record<string, unknown>>(
+  flag: string,
+  key: string,
+  options?: { min?: number },
+): FlagSpec<T>;
+export function booleanFlag<T extends Record<string, unknown>>(
+  flag: string,
+  key: string,
+  value?: unknown,
+  options?: { repeatable?: boolean },
+): FlagSpec<T>;
+export function parseFlagArgs<T extends Record<string, unknown>>(
+  argv: readonly string[],
+  args: T,
+  specs: readonly FlagSpec<T>[],
+  options?: ParseOptions<T>,
+): T;