PR Vision v0.3.0: per-call cost accountability + LLM call audit trail

P0 security:
- PRV_Gateway_Client: remove response body from RuntimeException (HTTP status only)
- PRV_Capture_Writer: allowlist-only write (prompt/response text, never headers/auth)
- Mandatory capture order: can_afford → probe → persist_result → update_row_cost → write_meta → capture_io
- capture_io last and wrapped in swallowing try/catch

New tables (SCHEMA_VERSION 3):
- prv_call_meta: cost/metadata per call, kept indefinitely
- prv_call_io: rendered prompt + raw response, pruned on retention window (default 90d)

New classes:
- PRV_Call_Meta_Table, PRV_Call_Io_Table: table schema + dbDelta
- PRV_Capture_Writer: metadata + I/O write; security allowlist enforced
- PRV_Prune_Cron: daily prv_daily_prune cron deletes aged prv_call_io rows only
- PRV_Cost_Rollup_Query: MTD summary, model breakdown, drill-down, projection
- PRV_Call_Log_Query: paginated + filtered call-log query + per-call I/O fetch
- PRV_Costs_Page + PRV_Costs_Renderer: Costs admin sub-page (cap progress, bento, model table, drill-down)
- PRV_Call_Log_Page + PRV_Call_Log_Table_Renderer: Call Log admin sub-page (filter bar, paginated table, WCAG AA pagination)
- PRV_Call_Drawer_Renderer: non-modal complementary drawer (5 states: Normal/Pruned/Legacy/Failed/Loading)
- PRV_Call_Drawer_Script: inline JS for drawer (300-line split from renderer)
- PRV_Call_Detail_Ajax: wp_ajax_prv_call_detail AJAX handler
- PRV_Admin_Page_Css: CSS provider (300-line split from PRV_Admin_Page)
- PRV_Probe_Run_Executor: inner probe loop (300-line split from PRV_Probe_Runner)

Updated:
- PRV_Probe_Result: tokens_in/tokens_out params + getters
- Both providers: report tokens_in/tokens_out from usage.prompt_tokens/completion_tokens
- PRV_Probe_Runner: slimmed to lock+UUID+delegation; injects PRV_Capture_Writer
- PRV_Config: get_io_retention_days(); PRV_IO_RETENTION_DEFAULT_DAYS constant
- PRV_Upgrader/Activator/Deactivator/Plugin: register new tables, cron, pages, AJAX
- Settings: retention days field + save in controller
- uninstall.php: DROP both new tables, clear prv_daily_prune cron
- Subnav 4-tab strip (Dashboard | Costs | Call Log | Settings) on all pages
- ARCHITECTURE.md, CHANGELOG.md, CONTEXT.md, CONVENTIONS.md updated

Tests:
- test-capture-writer.php: write_meta, write_io, P0 security (401 record has no key/Bearer/sk-or-)
- test-cost-audit.php: MTD reconciliation, projection, prune, forced capture_io exception, table drops

Agent-Session: peptiderepo-geomonitor-v0.3.0-cost-audit

ARCHITECTURE.md

@@ -1,6 +1,6 @@
 # Architecture — PR Vision
 
-**Version:** 0.2.1 | **Last updated:** 2026-06-14
+**Version:** 0.3.0 | **Last updated:** 2026-06-15
 
 ---
 
@@ -10,6 +10,7 @@
 
 **v1 scope:** AI-visibility only. The collector/panel seam is present so future data categories can be added as new classes.
 **v2 additions:** Model manager CRUD (no deploy needed), config-version tracking, run-lock, projected cost, API-key three-state, dark "Assay" Settings UI.
+**v0.3.0 additions:** Per-call cost/metadata + I/O audit trail; Costs + Call Log admin pages; non-modal detail drawer; daily I/O prune cron; `PRV_Gateway_Client` exception body removed (P0).
 
 ---
 
@@ -130,6 +131,41 @@ Admin page load ─────────────────────
 
 ## 4. Database
 
+### v0.3.0 additions
+
+**Table:** `{prefix}prv_call_meta` (kept indefinitely)
+
+| Column | Type | Notes |
+|--------|------|-------|
+| id | BIGINT UNSIGNED PK | Auto-increment |
+| visibility_row | BIGINT UNSIGNED NULL | FK to prv_ai_visibility.id (nullable) |
+| run_id | VARCHAR(36) | UUID for the run |
+| peptide_slug | VARCHAR(200) | e.g. "bpc-157" |
+| model | VARCHAR(200) | e.g. "perplexity/sonar" |
+| intent_label | VARCHAR(200) | Prompt intent template |
+| tokens_in | INT NULL | Input token count from API |
+| tokens_out | INT NULL | Output token count from API |
+| cost_usd | DECIMAL(12,8) | Actual call cost |
+| latency_ms | INT NULL | Call latency in ms |
+| cited | TINYINT(1) NULL | 1=cited, 0=not cited, NULL=error |
+| http_status | INT | HTTP status (200=ok, 4xx/5xx=error) |
+| captured_at | DATETIME | UTC |
+| config_version | INT NULL | Config version at run time |
+
+**Table:** `{prefix}prv_call_io` (pruned after retention window)
+
+| Column | Type | Notes |
+|--------|------|-------|
+| id | BIGINT UNSIGNED PK | Auto-increment |
+| call_id | BIGINT UNSIGNED | FK to prv_call_meta.id |
+| prompt_text | LONGTEXT | Rendered prompt (plain text) |
+| response_text | LONGTEXT | Raw LLM response text |
+| captured_at | DATETIME | UTC (indexed for prune query) |
+
+---
+
+## 4a. Original Database
+
 **Table:** `{prefix}prv_ai_visibility`
 
 | Column | Type | Notes |