refactor: runtime isolation — deprecate global singletons, add counter resets

config.ts: @deprecated on configure/getConfig/project/getProjectConfig.
  Current code has zero production callers — dead code path. Functions
  remain for backward compatibility but signal migration to scoped config.

context.ts: @deprecated on setDefaultContext. Documents that consumers
  should call resetDefaultContext() after use in tests to prevent
  context-seed leakage.

pipeline.ts: Export resetTraceCounter() for test isolation of _traceId
  counter variable.

extraction.ts: Export resetPageCacheNamespaceCounter() for test
  isolation of pageCacheNamespaceCounter.

Combined with prior fix (defaultPredicatesRegistered→sentinel check
+ compatibilityWarningEmitted→warnedUis WeakSet), 5 of 7 correctness-
  affecting global mutable state items are now tied down. Remaining:
  globalPredicateRegistry/globalClauseRegistry (already @deprecated
  with explicit injection path via LogicEngineOptions/EvalOptions).

605 SDK + 57 E2E = 662 tests pass.

packages/imhotep-dsl/src/config.ts

@@ -11,12 +11,12 @@ export interface ImhotepConfig {
 
 let globalConfig: ImhotepConfig = {}
 
-/** Sets or updates global Imhotep runtime configuration. */
+/** @deprecated Use explicit runtime-scoped configuration instead of global mutable state. */
 export function configure(config: ImhotepConfig): void {
   globalConfig = { ...globalConfig, ...config }
 }
 
-/** Returns a shallow copy of the current global config. */
+/** @deprecated Use explicit runtime-scoped configuration. Returns a shallow copy of the global config. */
 export function getConfig(): ImhotepConfig {
   return { ...globalConfig }
 }
@@ -31,12 +31,12 @@ export interface ProjectConfig {
 
 let projectConfig: ProjectConfig = {}
 
-/** Sets or updates project-level defaults, font corpora, and adapters. */
+/** @deprecated Use explicit runtime-scoped project config instead of global mutable state. */
 export function project(config: ProjectConfig): void {
   projectConfig = { ...projectConfig, ...config }
 }
 
-/** Returns a shallow copy of the current project config. */
+/** @deprecated Returns a shallow copy of the global project config. */
 export function getProjectConfig(): ProjectConfig {
   return { ...projectConfig }
 }