feat(v3.12.0): media pipeline, AI image generation, capability probe, companion v2.9.0

Three-month batch sync from internal repo (~80 commits) covering Tracks F.5a, F.7e, F.8, F.17, F.18, F.X.

WordPress media pipeline
- Pillow-based optimization, AI image generation (OpenAI / Stability / Replicate / Google Nano Banana / OpenRouter), chunked + resumable uploads, bulk delete/reassign, idempotent retries.

Capability discovery (F.7e)
- Per-site credential probe + adapters for WordPress / WooCommerce / Gitea, tier-fit unions granted ∪ roles, capability badge UI with HTMX partial re-check, install hint in every companion-unreachable error.

Companion plugin overhaul
- Renamed wordpress-plugin/airano-mcp-seo-bridge → wordpress-plugin/airano-mcp-bridge.
- Eight new endpoints: /capabilities, /bulk-meta, /export, /cache-purge, /transient-flush, /site-health, /audit-hook, /upload-and-attach.
- wp.org Plugin Check pass: i18n, WP_Filesystem, scheme allowlist on audit-hook URL.

Other
- Gitea ergonomics (F.17): batch files, tree, search, compare, releases, fork.
- Opportunistic bcrypt upgrade for legacy SHA-256 admin keys (F.8).
- n8n refactor: structured errors, capability probe, missing tools backfilled.
- Idempotency-Key dedup for AI media upload retries; WP client fast-fails on unreachable sites.

Docs
- README + CLAUDE.md drop the fixed "633 tools" claim. The total grows with each release; per-plugin approximations + dashboard-surfaced counts replace it.
- Tools/Tests badges removed in favour of "Plugins: 10".

Deployment
- PyPI mirror chain, optional BUILD_HTTP_PROXY, Alpine→Yandex apk mirror, Debian-slim Plan-B Dockerfile, mirror.gcr.io variant.

CI
- Black + Ruff clean on Python 3.12; pytest tests/ green.

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

plugins/wordpress/handlers/_companion_hint.py

@@ -0,0 +1,65 @@
+"""Shared ``companion_unreachable`` error-hint helper.
+
+Every companion-backed handler (cache_purge, bulk_meta, export,
+site_health, transient_flush, audit_hook, regenerate_thumbnails,
+capabilities) returns a structured JSON error when the companion
+plugin isn't installed / reachable. This module provides a single
+helper so the hint message, download URL, and install instructions
+stay in sync.
+
+F.20 will swap the download URL constant from the GitHub raw path to
+``wordpress.org/plugins/airano-mcp-bridge/`` once the wp.org listing
+is live. At that point a single edit here + the dashboard template
+(``core/templates/dashboard/sites/manage.html``) covers everything.
+"""
+
+from __future__ import annotations
+
+# Single source of truth for the companion download URL. Mirror of the
+# constant used in ``core/dashboard/routes.py``. Kept as a plain string
+# rather than imported to avoid a core→plugin import cycle.
+COMPANION_DOWNLOAD_URL = (
+    "https://github.com/airano-ir/mcphub/raw/main/" "wordpress-plugin/airano-mcp-bridge.zip"
+)
+
+
+def companion_install_hint(
+    *,
+    min_version: str,
+    required_capability: str = "manage_options",
+    route: str | None = None,
+) -> dict[str, str]:
+    """Return a ``hint`` dict that every companion-backed handler can
+    merge into its ``companion_unreachable`` payload.
+
+    Args:
+        min_version: Earliest companion plugin version that exposes the
+            route this handler uses (e.g. ``"2.4.0"``). Surfaced in the
+            install hint so the user knows what they need.
+        required_capability: WordPress capability the calling user needs
+            for the companion route. Default ``manage_options``.
+        route: Optional route path — included in the hint when set so
+            the user can sanity-check by hitting the endpoint directly.
+
+    Returns:
+        Dict with ``install_url``, ``install_instructions``, and
+        ``required_capability``. Callers merge into their existing
+        structured error response alongside ``error`` / ``message``.
+    """
+    instructions = (
+        f"Install the Airano MCP Bridge companion plugin (v{min_version}+) "
+        "on the WordPress site. Download the zip, then in the WP admin: "
+        "Plugins → Add New → Upload Plugin → select the file → Activate. "
+        f"Ensure the Application Password user has the ``{required_capability}`` "
+        "capability. Run ``wordpress_probe_capabilities`` to verify the "
+        "route is advertised."
+    )
+    out = {
+        "install_url": COMPANION_DOWNLOAD_URL,
+        "install_instructions": instructions,
+        "required_capability": required_capability,
+        "companion_min_version": min_version,
+    }
+    if route:
+        out["route"] = route
+    return out