docs: resolve ADR-014 migration-008 false alarm (cols shipped in 007)

Reconciliation finding: the v0.6.0 report's "migration 008 videos.rate_limited_at"
was a mislabel. Both transcript_status and rate_limited_at shipped in migration
007; the sequence legitimately skips 008, nothing was lost, and the runner's
column reads are sound. Updated the ADR-014 implementation note to state this
(was flagged as an unresolved discrepancy). The item-2 (shared per-egress-IP rate
gate vs per-video backoff) flag stays open — still unconfirmed.

DECISIONS.md

@@ -402,16 +402,17 @@ the rate gate (the batch path moves into k3s per the deferred CronJob item).
 
 **Implementation note (2026-06-03, v0.6.0 — added during reconciliation).** A v0.6.0 release
 shipped 429 handling: `domain.SourceRateLimited` (429 no longer collapsed to `SourceNone`),
-youtube adapter maps 429 → `SourceRateLimited`, migration 007 `transcript_status` + (per the
+youtube adapter maps 429 → `SourceRateLimited`, **migration 007 added `videos.transcript_status`
-v0.6.0 report) a `videos.rate_limited_at` column, `TAPIR_FETCH_BACKOFF` config, runner records
++ `videos.rate_limited_at`** (durable per-video retry state), `TAPIR_FETCH_BACKOFF` config,
-rate-limited + skips within the backoff window, and a "⏳ Retrying later" badge. This realises
+runner records rate-limited + skips within the backoff window, and a "⏳ Retrying later" badge.
-decision items 1, 3, and 4 well. **Item 2 (a single shared per-egress-IP rate gate) appears to
+This realises decision items 1, 3, and 4 well. **Item 2 (a single shared per-egress-IP rate
-be realised as per-*video* backoff state, NOT a process-wide IP gate** — multiple videos can
+gate) appears to be realised as per-*video* backoff state, NOT a process-wide IP gate** —
-still each hit the endpoint and collectively trip the per-IP 429. Treat item 2 as **not yet
+multiple videos can still each hit the endpoint and collectively trip the per-IP 429. Treat item
-confirmed done**; verify in `internal/runner`/youtube adapter and, if absent, it remains open.
+2 as **not yet confirmed done**; verify in `internal/runner`/youtube adapter and, if absent, it
-ALSO: the v0.6.0 report referenced "migration 008 videos.rate_limited_at" but **no migration 008
+remains open. (Resolved during reconciliation: the v0.6.0 report's reference to "migration 008
-exists on `main`** (tree jumps 007→009). Resolve whether `rate_limited_at` actually shipped (in
+videos.rate_limited_at" was a **mislabel** — both columns shipped in migration **007**, not a
-007? lost? renumbered?) — a documentation/build discrepancy flagged during reconciliation.
+missing 008. No migration was lost; the sequence legitimately skips 008. `rate_limited_at`
+exists and the runner's column reads are sound.)
 
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