docs(app-blocks): resolve the two docblocks that answer the reader twice, oppositely

Follow-on from the same re-check that found the agentic-review rot. Eleven docblocks
in this file carry an inherited "the flag does NOT exist in Flipt at merge time"
sentence; the new header frames all of them as as-merged history, which is the
deliberate treatment (substituting a fresher enumeration would be the same rot one
generation on).

But in exactly TWO docblocks that inherited sentence sits in the SAME block as a
live-state sentence I wrote, so the reader gets opposite answers eight lines apart:

  isAppListingsEnabled          "does NOT exist"  vs  "Both are base-`false` today"
  APP_BLOCKS_SHARED_STORAGE_FLAG "does NOT exist" vs  "Closed today because the base
                                                       is `false`"

Both inherited sentences moved to past tense and marked as as-merged notes. Nothing
else changed: the other eleven are untouched, because they carry no competing claim.

Criterion for the split, so it can be re-applied: fix where a paragraph contradicts
itself; leave where the header already governs.

Re-verified after the edit rather than carrying the previous measurement over — these
are comments, but they shift line numbers in a WATCHLISTED module, and source/artefact
correspondence is exactly what this PR stopped assuming. Fresh `next build` (green),
then the compiled-branch gate: positive OK on all three entries (26,600 maps; controls
mapped), negative control still exit 1 naming both new entries.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/server/services/app-blocks-flag.ts

@@ -293,12 +293,15 @@ export async function isAppBlocksEnabled(opts?: { user?: SessionUser }): Promise
  * difference: if `app-listings` resolves `false`, this FALLS BACK to
  * `isAppBlocksEnabled(opts)`. That fallback is the whole point of the dark
  * decoupling:
- *   - The `app-listings` flag does NOT exist in Flipt at merge time (created
- *     AFTER, as a companion `flipt-state` PR). A bare eval of an absent flag
- *     resolves `false` for EVERYONE — which would REGRESS the currently-visible
- *     cohort (mods + the `app-dev-testers` segment of `app-blocks-enabled`) the
- *     instant this merges. The OR-fallback to `app-blocks-enabled` preserves
- *     their store access verbatim through the transition window.
+ *   - The `app-listings` flag did NOT exist in Flipt when this merged (it was
+ *     created AFTER, as a companion `flipt-state` PR). A bare eval of an absent
+ *     flag resolves `false` for EVERYONE — which would have REGRESSED the
+ *     then-visible cohort (mods + the `app-dev-testers` segment of
+ *     `app-blocks-enabled`) the instant this merged. The OR-fallback to
+ *     `app-blocks-enabled` preserved their store access verbatim through that
+ *     transition window. (Past tense on purpose: this is an as-merged note, not
+ *     live state — see the reading trap at the top of this file. The paragraph
+ *     below says what closes this TODAY.)
  *   - Because `app-blocks-enabled` already grants the mods + app-dev-testers
  *     cohort today, `isAppListingsEnabled` grants EXACTLY that same set until the
  *     `app-listings` flag is created and later widened — so the as-merged change
@@ -729,9 +732,11 @@ export async function isAppBlocksAgenticReviewEnabled(opts?: {
  *
  * Create it in Flipt as base `enabled: false` with the `moderators` segment (+
  * any community-cohort segment) exactly like `app-blocks-dev-tunnel`. The flag
- * does NOT exist in Flipt at merge time — the companion `flipt-state` entry is a
- * SEPARATE follow-up PR — so the as-merged posture is fully dark and cannot
- * regress the gate open.
+ * did NOT exist in Flipt when this merged — the companion `flipt-state` entry was
+ * a SEPARATE follow-up PR — so the as-merged posture was fully dark and could not
+ * regress the gate open. (Past tense on purpose: this is an as-merged note, not
+ * live state — see the reading trap at the top of this file. The paragraph above
+ * says what closes this TODAY.)
  */
 export const APP_BLOCKS_SHARED_STORAGE_FLAG = 'app-blocks-shared-storage';