v0.8.2: CF images via AI Gateway + scheduled-gen timezone fix

* feat(images): route Cloudflare Workers AI via AI Gateway by default

Direct probe on 2026-04-21 confirmed the Cloudflare AI Gateway
route to Workers AI (`gateway.ai.cloudflare.com/.../workers-ai/@cf/...`)
is no longer 403ing — the upstream regression noted in v0.8.0's
ARCHITECTURE.md #16 and in thread image-pipeline seq 6 has been
resolved. Routing via the gateway gives us the same benefits we
already get for OpenRouter LLM calls: response caching, cost/latency
dashboard, rate limiting.

Changes:

- `Cloudflare_Image_Support::build_endpoint_url()` now prefers the
  gateway URL derived from the existing `prautoblogger_ai_gateway_base_url`
  option. Direct API remains the fallback.
- New private helper `build_gateway_workers_ai_url()` strips the
  OpenRouter path suffix from the configured gateway URL and appends
  `/workers-ai/{model}`. Returns empty string (fallback to direct) when:
  no gateway URL configured, the new toggle is off, or the URL isn't a
  valid `https://gateway.ai.cloudflare.com/...` shape.
- New admin toggle `prautoblogger_cf_image_via_gateway` (default on) in
  the Images section. Operators can disable to force direct API without
  clearing the LLM-path gateway URL.
- ARCHITECTURE.md #16 rewritten to reflect the v0.8.2+ gateway routing.
- CHANGELOG.md v0.8.2 entry under Changed.

Tests (new `CloudflareImageSupportTest`):

- Direct URL when gateway not configured.
- Gateway URL derived correctly when configured + toggle on.
- Toggle off forces direct URL even with gateway configured.
- Malformed gateway URL falls back to direct (defensive).
- `is_nsfw_error()` only matches error code 3030 (pinned separately so
  a tolerance regression fails early).

Cost impact: near-zero. Gateway adds a few ms of latency and enables
response caching — could *reduce* cost on identical prompts within the
configurable cache TTL.

Uninstall: new option covered by existing prautoblogger_% LIKE sweep.

Implements Commit 1b (narrow AI-Gateway-migration scope) per thread
image-pipeline seq 7.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* chore(cost): seed new toggles in activator defaults; tighten URL stripper

QA review on cd45ae2 surfaced two things; one real, one hallucinated:

- **Real (fixed):** `prautoblogger_cf_image_via_gateway` and v0.8.1's
  `prautoblogger_image_nsfw_retry` weren't seeded in
  `Activator::set_default_options()`. Belt-and-braces — the `get_option()`
  fallback at the read site already defaults to '1', so no user-visible
  regression exists, but seeding the options follows the established
  pattern for every other plugin setting and makes intent legible to
  operators inspecting `wp_options` directly.
- **Hallucinated (rejected):** the reviewer claimed
  `CloudflareImageSupportTest` methods 2–5 were empty stubs. Verified
  — every test has real `$this->assert*` calls (10 total across the 5
  cases). Ignoring. Flagging the false-positive to the CTO per the
  qa-review quality-tracking protocol.

Also clarified the docblock + tightened the ternary inside
`build_gateway_workers_ai_url()` — explicit `strrpos` false-check
instead of the `?:` short-circuit, so a no-slash base (defensive edge)
falls through cleanly instead of returning a weirdly-sliced URL.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* fix(schedule): interpret `prautoblogger_schedule_time` in site timezone

Per thread scheduled-gen-timezone seq 1: WordPress core calls
`date_default_timezone_set('UTC')` early in bootstrap, so the activator's
`strtotime("tomorrow HH:MM")` was resolving in UTC regardless of the
site's configured timezone. On peptiderepo.com (Asia/Singapore, UTC+8)
a `schedule_time` of `06:00` fired at 14:00 local.

Fold this into the existing v0.8.2 branch (PR #102) since both this fix
and the earlier CF-image-gateway change target the same version and
touch overlapping files (activator, settings-fields-extended).

Changes:

- `Activator::next_daily_generation_timestamp()` — new public helper
  that reads `prautoblogger_schedule_time`, constructs a
  `DateTimeImmutable('tomorrow', wp_timezone())`, applies the
  configured hour/minute, returns a Unix timestamp. Defensive fallback
  to the old UTC-interpretation behaviour on any DateTime parse error
  so a bad tz string can't brick the schedule.
- `Activator::schedule_cron()` delegates to the helper instead of
  calling `strtotime` directly.
- New `Activator::reschedule_daily_in_site_timezone_v082()` — one-shot
  migration that clears the stale UTC-scheduled event and re-queues
  using the helper. Gated by `prautoblogger_migrated_schedule_tz_v082`
  option so it runs exactly once. Logs an INFO line comparing
  before/after next_run for auditability.
- `class-prautoblogger.php::on_check_db_version()` invokes the
  migration on every admin_init; the one-shot flag handles re-run
  guarding (no DB_VERSION bump needed — the migration is independent
  of the schema version).
- Settings description for "Generation Time" now says
  "...in your site's configured timezone (Settings → General →
  Timezone). Current site timezone: <wp_timezone_string()>" instead
  of the ambiguous "server timezone" phrasing.

File-size compliance:
- Adding the timezone helpers pushed `class-activator.php` to 352
  lines. Extracted the 104-line `create_tables()` SQL to a new
  `class-schema-installer.php` (136 lines). Activator now 245 lines,
  schema file fully dedicated to dbDelta.

Tests (new):

- `ActivatorScheduleTest` — SGT 06:00 → 22:00 UTC prev day; UTC 06:00
  → 06:00 UTC (no-op case); Asia/Kathmandu UTC+5:45 → 00:15 UTC
  (fractional offset); malformed time input doesn't throw.
- `ActivatorMigrationTest` — pre-seeded UTC cron gets cleared and
  rescheduled in SGT; second pass is idempotent.

CHANGELOG v0.8.2 entry now also covers the timezone fix under Fixed +
the description wording change under Changed.

Implements thread `scheduled-gen-timezone` seq 1 spec.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: peptiderepo <peptiderepo@users.noreply.github.com>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

ARCHITECTURE.md

@@ -533,8 +533,8 @@ Reddit rejected our OAuth API application (April 2026). We initially switched to
 
 The admin model picker (v1) needs to list OpenRouter models with pricing and capabilities. We fetch `https://openrouter.ai/api/v1/models` (free, unauthenticated) once daily and store the normalized payload in a WP option fronted by a 24h transient. On stale-and-fetch-fails, we serve last-good + surface a warning. The registry class (`class-open-router-model-registry.php`) takes all config via constructor (option name, transient name, endpoint URL) — no PRAUTOBLOGGER_* constants inside the class body. Phase 2 lifts it into a shared Composer package with zero internal edits. Phase 3 adds a parallel `Cloudflare_WorkersAI_Model_Registry` behind the same interface. Capability vocabulary: `text→text`, `text+image→text`, `text+audio→text`, `text→image`, `text→audio`, `text→video`, `text→embedding`. Cost: $0/month.
 
-### #16: Image generation via Cloudflare Workers AI (FLUX.1), direct (not via AI Gateway)
-The image-generation layer (started 2026-04-15, tracked in `convo/prautoblogger/threads/2026-04-image-pipeline/`) uses FLUX.1 [schnell] on Cloudflare Workers AI as its default model, chosen for its ~$0.0011/MP cost and 2–3 sec latency. FLUX.1 [dev] is a ~4× cost upgrade exposed as a dropdown for specific posts that warrant it. Calls go directly to `https://api.cloudflare.com/client/v4/accounts/{id}/ai/run/@cf/black-forest-labs/...`, *not* through the Cloudflare AI Gateway that we use for OpenRouter — the gateway route to Workers AI currently 403s (pre-existing open issue). The provider lives behind `PRAutoBlogger_Image_Provider_Interface`, so the decision is trivially reversible: switching to a different image API (DALL-E, Replicate, a future AI Gateway route) is a new class implementation plus a one-line swap in the pipeline wiring. Trade-off: we run two different Cloudflare integration paths (gateway for OpenRouter LLMs, direct for Workers AI images) until the gateway route stabilizes — minor cognitive overhead, zero functional downside.
+### #16: Image generation via Cloudflare Workers AI (FLUX.1), via AI Gateway (v0.8.2+)
+The image-generation layer uses FLUX.1 [schnell] on Cloudflare Workers AI as its default model, chosen for its ~$0.0011/MP cost and 2–3 sec latency. FLUX.1 [dev] is a ~4× cost upgrade exposed as a dropdown for specific posts that warrant it. **v0.8.2+**: calls route through the Cloudflare AI Gateway (same gateway we already use for OpenRouter — `gateway.ai.cloudflare.com/v1/{account}/{gateway}/workers-ai/@cf/black-forest-labs/...`) for response caching, unified cost/latency telemetry, and rate limiting. The 2026-04-15 regression that caused the gateway route to 403 on Workers AI has been resolved upstream; verified by direct probe on 2026-04-21. A `prautoblogger_cf_image_via_gateway` toggle (default on) falls back to the direct `api.cloudflare.com/client/v4/accounts/{id}/ai/run/...` URL if the gateway regresses again. The provider lives behind `PRAutoBlogger_Image_Provider_Interface`, so switching to a different image API (DALL-E, Replicate) is a new class implementation plus a one-line swap in the pipeline wiring.
 
 ### #15: Optional Cloudflare AI Gateway in front of OpenRouter
 We already use Cloudflare for DNS/CDN on peptiderepo.com, so layering AI Gateway in front of OpenRouter is zero marginal infrastructure. It gives us response caching (meaningful for repeated classification/scoring calls), a unified cost/latency dashboard, rate limiting, and provider fallback — all of which we would otherwise have to build ourselves to satisfy the CTO cost-tracking rules. Kept as an opt-in URL setting (`prautoblogger_ai_gateway_base_url`) so the plugin still works unchanged out of the box and can be bypassed instantly if the gateway misbehaves. The gateway is a transparent OpenRouter-compatible proxy; no new provider class is needed, and the response parsing path (`usage`, `choices[0].message.content`) is unchanged.