feat: M4 in-admin manual generation on chained-cron checkpoints + IA/perf pass (v0.21.0) (#166)

Final Phase 2 admin milestone. Board "New Article" runs through the M3 chained-cron checkpoint state machine (one stage/idea per tick, queue persisted before generate, lock released on every exit path) so generation survives Hostinger background-kill; retires the SSH-only do_action workaround (WP-CLI routes through the same entry). IA/perf: settings-backed board/ideas pagination + db 1.4.0 indexes. Folds guard P2s (--self-test + window doc).

QA: APPROVE-WITH-P2-NOTES @ f2a00d4 + delta APPROVE @ 0c8071f. Deferred (tracked): class-admin-page.php 353-line split + pagination Settings-UI fields.

Agent-Session: phase2-admin-m4-20260614

INFORMATION-ARCHITECTURE.md

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+# Information Architecture — PRAutoBlogger
+
+Auto-generated index of all admin surfaces, data flows, and integrations.
+Maintained per DoD v1.1.0 (same-PR update rule).
+
+---
+
+## Admin Pages
+
+| Slug | Class | Template | Purpose |
+|------|-------|----------|---------|
+| `prautoblogger-settings` | `PRAutoBlogger_Admin_Page` | `admin-page.php` | Main settings (schedule, models, budget, board limits) |
+| `prautoblogger-board` | `PRAutoBlogger_Board_Page` | `board-page.php` | Kanban board: Generating / Failed / In Review / Published columns. New Article button (v0.21.0). |
+| `prautoblogger-articles` | `PRAutoBlogger_Articles_Page` | `articles-page.php` | Paginated list of all articles/runs |
+| `prautoblogger-dossier` | `PRAutoBlogger_Dossier_Page` | `dossier-page.php` | Per-article generation log + stage edit/re-run (M3) |
+| `prautoblogger-ideas` | `PRAutoBlogger_Ideas_Browser` | `ideas-browser.php` | Analysis results browser with per-idea generation |
+| `prautoblogger-activity` | `PRAutoBlogger_Activity_Page` | `activity-page.php` | Cost + generation activity log |
+
+---
+
+## Generation Entry Points (v0.21.0)
+
+```
+Board "New Article" button
+  └─ AJAX prautoblogger_generate_now
+       └─ Generation_Status_Poller::on_ajax_generate_now()
+            └─ schedules prautoblogger_manual_generation cron
+                 └─ Executor::on_manual_generation()
+                      └─ Generation_Checkpoint_Runner::on_orchestrate_tick()  ← Tick 1
+                           └─ schedules prautoblogger_gen_tick
+                                └─ Generation_Checkpoint_Runner::on_generate_tick()  ← Tick 2..N
+
+WP-CLI: wp prautoblogger generate
+  └─ WP_CLI_Commands::generate_command()
+       └─ Generation_Checkpoint_Runner::kick_off()
+            └─ schedules prautoblogger_gen_orchestrate
+                 └─ Generation_Checkpoint_Runner::on_orchestrate_tick()  ← Tick 1
+
+Daily auto-generation cron
+  └─ prautoblogger_daily_generation
+       └─ Executor::on_cron_run()
+            └─ Pipeline_Runner::run()  (legacy synchronous path — runs in a single PHP process)
+```
+
+---
+
+## Database Tables
+
+| Table | DB Version | Purpose |
+|-------|-----------|---------|
+| `prautoblogger_sources` | 1.0.0 | Collected Reddit/RSS source content |
+| `prautoblogger_analysis_results` | 1.0.0 | Scored article ideas |
+| `prautoblogger_generation_log` | 1.0.0 | Per-LLM-call log (cost, tokens, status) |
+| `prautoblogger_runs` | 1.0.0 | Per-run ledger (status, ceiling_usd) |
+| `prautoblogger_run_stages` | 1.2.0 | Per-stage state for M3 re-run |
+| `prautoblogger_stage_inputs` | 1.3.0 | Immutable input versions for stage edits (M3) |
+| `prautoblogger_run_decisions` | 1.2.0 | Editorial decisions per run |
+
+DB version history: 1.0→1.1 (schema normalisation), 1.1→1.2 (M2 dossier), 1.2→1.3 (M3 stage inputs), 1.3→1.4 (M4 indexes).
+
+---
+
+## Key Options
+
+| Option | Type | Default | Purpose |
+|--------|------|---------|---------|
+| `prautoblogger_board_column_limit` | int | 20 | Max cards per board column |
+| `prautoblogger_ideas_per_page` | int | 30 | Ideas browser page size |
+| `prautoblogger_article_queue` | array | — | Checkpoint queue (run_id + ideas + results) |
+| `prautoblogger_checkpoint_run_id` | string | — | Current run UUID for Tick 2..N finalize path |
+| `prautoblogger_db_version` | string | — | Installed schema version (triggers dbDelta on mismatch) |
+
+---
+
+## WP-CLI Commands
+
+| Command | Since | Description |
+|---------|-------|-------------|
+| `wp prautoblogger generate` | 0.21.0 | Queue article generation via chained-cron checkpoints |
+| `wp prautoblogger opik:eval` | 0.12.0 | Trigger Opik eval run |
+
+---
+
+*Last updated: v0.21.0 (2026-06-14)*