Make main the lean product a site receives

main was 16 days and 259 commits behind the line the product is actually built
on, at contract 0.30.0 against 0.35.0, with no per-PC credential code at all. It
was neither current nor curated - just stale. This brings it forward and, at the
same time, makes it mean something: main is what a receiving site installs, and
nothing else.

WHAT IT CARRIES. Twelve plugins - backups, computers, endpoints, guides,
knowledgebase, machines, network, notifications, printers, slides, tools,
warranty - plus applications, which is manifest-less core and always ships. The
only manifest dependency inside that set is endpoints on computers, and both are
in it, so the closure is self-contained.

WHAT IT DOES NOT. employees, geenforce, measuringtools, printedparts and usb
stay on the site line. So do the Windows installer tree, the VM rehearsal
helpers, the agent tooling config, one site's data loader, the internal audit
and findings records, and the planner spreadsheet. 1,135 tracked files against
1,438.

A REMOVAL THAT BREAKS THE APP IS NOT A REMOVAL, and two nearly shipped:

deploy/site-profile-universal.json still named all seventeen plugins. It is the
file docs/DEPLOY.md tells a site to provision from, so a fresh install would
have failed at `flask plugin apply-profile` with PluginError - the first thing a
receiving site does, broken by the branch meant to serve them. It now names the
twelve that exist, and its comment says the two must agree.

agent/ was never refreshed. Whoever populated this branch copied shopdb/,
plugins/, frontend/ and tests/ from the site line and left the agent tree at its
September state: 22 C# and PowerShell sources missing, including AgentCredentials,
EnrollmentService, AgentHttpFactory and the fleet-alert client, plus one file the
site line had deleted still present. The old tree is internally consistent, so it
compiles, and nothing in CI builds it - every gate was green over a server that
speaks enrollment and per-PC credentials to a bundled agent source that cannot.
Resynced whole.

DECISIONS THIS ENCODES, rather than defers:

- The plugin-authoring lab builds printedparts, whose manifest depends on
  employees, so it could not stay. The lab remains on the site line and main
  ships no build-along tutorial. That is a real loss for an adopting developer
  and is recorded here rather than discovered later.
- Recognition, Training and Recertification notifications are no longer seeded.
  Each splits one notification into a card per employee and renders a photo,
  which needs a plugin this branch does not bundle. Seeding them would offer an
  author a type that cannot resolve anybody. A site that installs employees gets
  them from that plugin's own seed.
- Windows/IIS is documented as the legacy path throughout, and the README leads
  with Docker, because that is what a receiving site gets.

The API description is regenerated for THIS branch - 347 paths and 483
operations, down from 415 and 573 - so the published contract describes what is
here rather than what the site line serves. docs/CONFIG.md lost the two
measuring-tool label keys the code no longer declares, which two lanes had
decided opposite ways.

Suite: 3124 passed, 6 skipped. Naming and style gates pass. The docs gates run
rather than skip, and every index line count is derived from the file it names.

shopdb/plugins/__init__.py

@@ -4,8 +4,9 @@ from pathlib import Path
 from typing import Dict, List, Optional
 from flask import Flask
 import logging
+import re
 
-from .base import BasePlugin, PluginMeta
+from .base import BasePlugin, PluginMeta, renderable_settings_routes
 from .registry import PluginRegistry, PluginState
 from .loader import PluginLoader
 from .migrations import PluginMigrationManager
@@ -102,6 +103,22 @@ class PluginManager:
 
         for name, plugin in plugins.items():
             self._register_plugin_components(plugin)
+            self._check_settings_routes(name, plugin)
+
+    def _check_settings_routes(self, name: str, plugin: BasePlugin) -> None:
+        """Say at boot, once per plugin, if a declared settings tab is dead.
+
+        Only some settings hubs draw plugin tabs (see
+        SETTINGS_HUBS_WITH_PLUGIN_TABS). A route for any other hub is accepted
+        by the hook and returned by the API and then rendered by nobody, which
+        looks from every side like the plugin is at fault. The API drops such a
+        route; this makes the same finding at startup, so it is in the log of a
+        site that never opens the settings page."""
+        try:
+            renderable_settings_routes(name, plugin.get_settings_routes(),
+                                       logger)
+        except Exception:
+            logger.exception("get_settings_routes failed for %s", name)
 
     def upgrade_all_plugins(self) -> Dict[str, str]:
         """Run pending Alembic migrations for every discovered plugin.
@@ -119,6 +136,13 @@ class PluginManager:
         # upgrade is the only moment left to seed them. Runs even with no
         # migration manager - it is independent of the Alembic chains.
         self.sync_all_plugin_settings()
+        # Permissions need the same treatment for the same reason. A permission
+        # added in a later plugin version would otherwise exist only after a
+        # manual `flask seed permissions`, and until someone ran it the route
+        # guarding on that name would refuse every caller - including admins on
+        # sites that gate by permission rather than role. Deploys run
+        # upgrade-all, so this is the moment the new name has to appear.
+        self.sync_all_plugin_permissions()
         if not self.migration_manager:
             return results
         # Only ADOPTED plugins (those in the registry) get migrated. A plugin
@@ -158,6 +182,51 @@ class PluginManager:
                 touched += 1
         return touched
 
+    def sync_all_plugin_permissions(self) -> int:
+        """Seed every enabled plugin's declared permissions, then relink scopes.
+
+        Returns the number of plugins whose permissions were seeded. Best-effort
+        per plugin: one bad plugin must not abort a deploy's upgrade pass.
+
+        The scope relink is the load-bearing half. Creating the Permission row
+        only makes the name exist; the prebuilt scopes derive their grants from
+        the catalog, so a permission seeded without a following
+        Role.seedscopes() belongs to nobody but admin. The symptom is a plugin
+        that installs cleanly and whose UI is invisible to every non-admin until
+        someone re-runs the seed by hand. Ordering matters for the same reason
+        it does in `flask seed permissions`: seedscopes only links rows that
+        already exist, so it runs last.
+        """
+        touched = 0
+        for name in list(self.registry.get_all().keys()):
+            if not self.registry.is_enabled(name):
+                continue
+            try:
+                plugin = self.loader.load_plugin(name, self._app, self._db)
+            except Exception:
+                logger.exception(
+                    "Could not load %s to sync its permissions", name)
+                continue
+            if plugin:
+                self._seed_plugin_permissions(plugin)
+                touched += 1
+
+        # Additive: this can hand a scope a newly declared permission, never
+        # take one away, so a site's deliberate role edits survive the deploy.
+        from shopdb.core.models import Role
+        try:
+            with self._app.app_context():
+                result = Role.seedscopes()
+                self._db.session.commit()
+                granted = sum((result or {}).get('granted', {}).values())
+                if granted:
+                    logger.info(
+                        "Linked %d new scope grant(s) after plugin upgrade",
+                        granted)
+        except Exception:
+            logger.exception("Could not relink prebuilt scopes after upgrade")
+        return touched
+
     def get_declared_plugin_settings(self) -> Dict[str, dict]:
         """Return {key: declared entry} across all loaded plugins.
 
@@ -468,11 +537,25 @@ class PluginManager:
         return True
 
     def enable_plugin(self, name: str) -> bool:
-        """Enable a disabled plugin."""
-        if not self.registry.is_installed(name):
-            logger.error(f"Plugin {name} is not installed")
+        """Enable a disabled plugin. Auto-installs if available but not installed."""
+        # Security: Validate plugin name to prevent path traversal
+        # Only allow alphanumeric, underscore, and hyphen (matches existing plugins)
+        if not re.match(r'^[a-zA-Z0-9_-]+$', name):
+            logger.error(f"Invalid plugin name format: {name}")
             return False
 
+        # Reject reserved names that could be used for directory traversal
+        if name in ('.', '..', ''):
+            logger.error(f"Invalid plugin name: {name}")
+            return False
+
+        # Auto-install if available but not installed (UX: enabling should just work)
+        if not self.registry.is_installed(name):
+            logger.info(f"Plugin {name} not installed, installing first")
+            if not self.install_plugin(name):
+                logger.error(f"Failed to install plugin {name}")
+                return False
+
         if self.registry.is_enabled(name):
             logger.info(f"Plugin {name} is already enabled")
             return True