perf: bound request work and resource usage (#866)

* perf: bound request work and resource usage

* fix: address performance review regressions

* fix: guard content expiration and dashboard state

* fix: tolerate cache outages and retire derived paths

* fix: revalidate expiration claims and status pagination

* fix: retry interrupted repository metadata cleanup

* fix: retire obsolete content cache storage

* fix: activate tree metadata and recheck expiration claims

* fix: fence cache publication across expiration

* fix: recover staged trees and enforce cache lifecycle cleanup

* fix: prune expired transforms during database outages

* fix: finish conference removals and reload expiration candidates

src/core/content-generation.ts

@@ -0,0 +1,9 @@
+import { createHash } from "crypto";
+export function contentGenerationPrefix(generation: string) {
+  return `__content/${createHash("sha256").update(generation).digest("hex")}`;
+}
+
+export function contentRetirementMarker(prefix: string) {
+  if (!/^__content\/[a-f0-9]{64}$/.test(prefix)) throw new Error("Invalid content generation prefix");
+  return `__content/__retired/${prefix.slice("__content/".length)}.txt`;
+}