fix(qa-evidence,observer): reject placeholder metadata and replay-only learning; declare the docs atomic-write target

- materialize measures revision, runtime and cwd itself and rejects supplied
  values that differ (CI run wrote revision "HEAD" and runtime "bun"), and
  refuses learning checkpoints that replay the same probe, naming the fix.
- The docs write observer treats Claude Code's atomic temp for the authorized
  doc target as transient, so a temp renamed before its per-file watch no
  longer marks the observation incomplete (ship-docsync-completion flake).
  Per-file monitoring outside declared targets stays fail-closed.

test/helpers/qa-functional-observer.ts

@@ -72,7 +72,7 @@ export interface QAWriteObservation {
   limits: string[];
 }
 
-export async function observeQAWrites(root: string, options: { reportDirectory?: string; evidenceProducer?: boolean } = {}) {
+export async function observeQAWrites(root: string, options: { reportDirectory?: string; evidenceProducer?: boolean; atomicTargets?: string[] } = {}) {
   if (process.platform !== 'linux') throw new Error('QA write observer unavailable: Linux inotify required');
   if (fs.realpathSync(root) !== root) throw new Error('Observer root must be canonical');
   let reportDirectory: string | undefined;
@@ -82,7 +82,8 @@ export async function observeQAWrites(root: string, options: { reportDirectory?:
     reportDirectory = path.relative(root, directory);
   }
   const transientFile = (relative: string) => qaWriteAllowed(relative, 'qa-only')
-    || (reportDirectory !== undefined && relative.startsWith(reportDirectory + path.sep));
+    || (reportDirectory !== undefined && relative.startsWith(reportDirectory + path.sep))
+    || (options.atomicTargets ?? []).some(target => relative.startsWith(target + '.tmp.') && /^\.tmp\.[1-9]\d*\.[0-9a-f]{12}$/.test(relative.slice(target.length)));
   const before = qaTreeSnapshot(root);
   const { dlopen, FFIType, ptr } = await import('bun:ffi');
   const libc = dlopen('libc.so.6', {