fix(34): WR-06 bound the Plugins screen's search cache

pluginCatalog.lists was keyed by every distinct query and category and
never dropped an expired entry, so searching distinct strings grew the
process without limit (each entry can hold a 4 MiB answer). Storing a
search into a full cache now drops the expired searches and then the
ones that expire first, keeping at most 256.

modules/cabana/README.md

@@ -57,7 +57,7 @@ Use cases:
 - Roles screen: Settings → System → Roles (controller `cabana.RolesControllerID`, permission `cabana.PermissionManageRoles`) lists, creates, edits and deletes backend roles with name, code (slugged from the name), description and a checkbox permission editor. System roles (`is_system`, or a code that code-declared `pact.Permission` grants attach to) keep their code and cannot be deleted, a role any administrator holds (deleted ones included) cannot be deleted, a code another role uses is refused, and a non-superuser editor cannot add or remove a permission they lack. The update form's Administrators tab lists the role's holders read-only (a form partial): superusers only for superuser editors, deleted and deactivated holders marked, the first 100 with a note naming the total, each login linked to the Administrators preview for an editor holding `cabana.PermissionManageUsers`; roles are assigned only on the Administrators form.
 - Record actions on another plugin's controller: a plugin implementing `pact.HasAdminActionExtensions` adds `pact.AdminRecordAction` entries to any admin controller by its ID (`pact.AdminActionExtension`), its own, another plugin's or the admin's own Administrators screen (`cabana.AdministratorsControllerID`). They are merged at boot after the target's own record actions, in plugin activation order, offered on the target's preview screen and run through the same row-locked record action route; the target's `RequiredPermissions` and the action's own `Permissions` both apply. Contributions targeting `cabana.AdministratorsControllerID` run `guardOutranked` before `Run` (403 `user.outranked`, `Run` not called). An unknown controller ID, a target without a preview block, a name the target already registers (the owner's or an earlier contribution), a reserved or non-identifier name, a missing `Run` or an empty label stops the boot. Extensions are compiled only when the admin is active.
 - Form fields on another plugin's controller: a `pact.AdminActionExtension` with `Form` set to a `pact.AdminFormExtension` places fields and tabs in any admin controller's form by its ID. Its fields document is the `fields.yaml` format plus `before:`/`after:` anchors, `zone:` (only the tab zone for now) and a `tabs:` list, compiled at boot with every `fields.yaml` check; extensions apply in plugin activation order and the form is sent in the compiled order, so the SPA adds no ordering. `Hide` removes owner fields, `Permissions` and `Visible` decide per request who sees the fields (schema, show and save alike), widget fields run the extension's `Actions` and partial fields render from its `Dir` through `PartialData`. Extension values leave the save body before any owner path reads them; `Save` runs in the record's save transaction after the owner row is written (`pact.AdminFormErrors` answers 422, its notices join `meta.notices`) and `Load` serves the values on show. A form no extension lays out compiles unchanged. Unknown anchors, duplicate names, anchor cycles, anchors outside `Requires()`, other zones, `fileupload` fields and clashing widget action or partial names stop the boot naming the plugin, the controller and the name.
-- Plugins screen: Settings → System → Plugins opens the admin SPA route `/system/plugins` (the settings entry carries `path` instead of a controller) for administrators holding `cabana.PermissionViewPlugins` (`backend.view_plugins`, granted to no role in code; superusers always pass). GET `/plugins` lists the plugins the application was built with from the `party.Installed` metadata `summer build` bakes (name, description, version, source, module and package), or only the IDs of `party.Activated` for an application built before that metadata existed, with the framework version and the state of the plugin registry (`plugins.registry_url`, read through `kiosk.RegistryURL`). With the registry configured, cabana (never the SPA) looks up each versioned plugin's releases through `kiosk.Client` and marks an update when `kiosk.NewestCompatible` finds a release newer than the installed version by `kiosk.Newer` (a `git describe` string or a pseudo-version compares by the tag it builds on), with the `summer plugin:update <id>` command; GET `/plugins/marketplace` searches the registry and adds installed and compatibility markers and the `summer plugin:install <id>` command. Registry calls have a 4 second timeout, at most four run at once, and answers are cached in process (searches 5 minutes, releases 15 minutes, failures 1 minute); a failing registry gives `status` unavailable and never a non-200 answer.
+- Plugins screen: Settings → System → Plugins opens the admin SPA route `/system/plugins` (the settings entry carries `path` instead of a controller) for administrators holding `cabana.PermissionViewPlugins` (`backend.view_plugins`, granted to no role in code; superusers always pass). GET `/plugins` lists the plugins the application was built with from the `party.Installed` metadata `summer build` bakes (name, description, version, source, module and package), or only the IDs of `party.Activated` for an application built before that metadata existed, with the framework version and the state of the plugin registry (`plugins.registry_url`, read through `kiosk.RegistryURL`). With the registry configured, cabana (never the SPA) looks up each versioned plugin's releases through `kiosk.Client` and marks an update when `kiosk.NewestCompatible` finds a release newer than the installed version by `kiosk.Newer` (a `git describe` string or a pseudo-version compares by the tag it builds on), with the `summer plugin:update <id>` command; GET `/plugins/marketplace` searches the registry and adds installed and compatibility markers and the `summer plugin:install <id>` command. Registry calls have a 4 second timeout, at most four run at once, and answers are cached in process (searches 5 minutes, at most 256 distinct searches with expired and then the oldest dropped first, releases 15 minutes, failures 1 minute); a failing registry gives `status` unavailable and never a non-200 answer.
 - Administrators screen: when some plugin registers admin controllers, `cabana.Activate` also compiles the admin's own screens, an internal plugin with ID `summercms.cabana`. Settings → System → Administrators (controller `cabana.AdministratorsControllerID`, permission `cabana.PermissionManageUsers`) lists backend administrators with their role and last sign-in, opens a preview of each, where record actions (the admin's own and contributed ones) are offered, and creates and edits administrators: login, email, names, a password (hashed at `admin.password.bcrypt_cost`, at least 4 characters and at most 72 bytes), the role and per-administrator permission overrides. The server enforces the privilege rules in the save transaction: only a superuser sees superusers or sends the superuser switch, an administrator can neither grant permissions or roles above their own grants nor change an administrator who holds more than they do, their own role, superuser flag, permissions and password are not changed here, and the last active superuser cannot be demoted. A password set for another administrator ends their sessions (personal API tokens stay valid, as with `admin:reset-password`). Administrators are activated, deactivated and restored by record and bulk actions and deleted softly through `deleted_at` (never hard-deleted); the list shows deleted and deactivated rows with their row states and filters deleted ones, and the preview shows a status hint. Deactivating or deleting an administrator ends their sessions and stops their personal API tokens; the last active superuser cannot be demoted, deactivated or deleted on any of these paths (a transaction-scoped advisory lock serializes the check). The permission codes `cabana.PermissionManageUsers` and `cabana.PermissionManageRoles` are registered with no role grant, so after an upgrade only superusers see the screens until an administrator grants them. An application without admin controllers still activates no admin.
 - Danger record actions: `pact.AdminRecordAction.Danger` is served as `danger` on the record response's `cabana.RecordAction` (absent when false, so existing payloads are unchanged); the admin's confirm dialog then uses its danger variant.
 - Prompted record actions: a `pact.AdminRecordAction` with a `Prompt` (`pact.AdminActionPrompt`) asks the administrator for one text value in its confirm dialog. The record response serves it as `prompt` on the action's `cabana.RecordAction` (absent for every other action, so existing payloads are unchanged), and the action route accepts the body key `payload`, a JSON string, only for such an action: trimmed, not empty and at most `max_length` runes (422 on `payload` with `backend::lang.form.action_prompt_required` or `action_prompt_too_long`, `backend::lang.form.action_prompt_invalid` for another JSON type), then handed to `Run` as `pact.AdminRecordActionInput.Value`. Every other record action keeps refusing `record_id`, `values` and `payload`. A prompt without a label fails boot, owned or contributed.

modules/cabana/plugins.go

@@ -133,6 +133,9 @@ const (
 	registryFailureTTL  = time.Minute
 	registryLookups     = 4
 	marketplaceMaxQuery = 100
+	// marketplaceCacheSize bounds the cached searches: every distinct
+	// query is a key, so the map must not grow with them (WR-06).
+	marketplaceCacheSize = 256
 )
 
 var (
@@ -247,11 +250,35 @@ func (c *pluginCatalog) list(ctx context.Context, q, category string) (kiosk.Lis
 		resp, ttl = kiosk.ListResponse{}, registryFailureTTL
 	}
 	c.mu.Lock()
-	c.lists[key] = cachedList{resp: resp, err: err, expires: c.now().Add(ttl)}
+	c.storeList(key, cachedList{resp: resp, err: err, expires: c.now().Add(ttl)})
 	c.mu.Unlock()
 	return resp, err
 }
 
+// storeList caches a search under key with c.mu held. It first drops the
+// expired searches and then, while the cache is full, the one that
+// expires first, so it never holds more than marketplaceCacheSize.
+func (c *pluginCatalog) storeList(key string, entry cachedList) {
+	if _, ok := c.lists[key]; !ok && len(c.lists) >= marketplaceCacheSize {
+		now := c.now()
+		for k, v := range c.lists {
+			if !now.Before(v.expires) {
+				delete(c.lists, k)
+			}
+		}
+		for len(c.lists) >= marketplaceCacheSize {
+			oldest, first := "", true
+			for k, v := range c.lists {
+				if first || v.expires.Before(c.lists[oldest].expires) {
+					oldest, first = k, false
+				}
+			}
+			delete(c.lists, oldest)
+		}
+	}
+	c.lists[key] = entry
+}
+
 // releases returns the releases of plugin id, cached. listed is false when
 // the registry does not know the ID (a 404 is an answer, not a failure).
 func (c *pluginCatalog) releases(ctx context.Context, id string) ([]kiosk.RegistryVersion, bool, error) {

modules/cabana/plugins_test.go

@@ -264,6 +264,37 @@ func TestPluginsEndpoints(t *testing.T) {
 		}
 	})
 
+	t.Run("search cache is bounded", func(t *testing.T) {
+		reg := &memPluginRegistry{}
+		clk := &testClock{now: clock.Now()}
+		c := &pluginCatalog{registry: reg, timeout: time.Second, now: clk.Now, lists: map[string]cachedList{}, versions: map[string]cachedVersions{}}
+		for i := 0; i < marketplaceCacheSize+50; i++ {
+			clk.advance(time.Millisecond)
+			if _, err := c.list(t.Context(), fmt.Sprintf("q%d", i), ""); err != nil {
+				t.Fatal(err)
+			}
+		}
+		if n := len(c.lists); n != marketplaceCacheSize {
+			t.Fatalf("cached searches = %d, want at most %d", n, marketplaceCacheSize)
+		}
+		// The oldest went first; the newest is still a hit.
+		if _, ok := c.lists["q0\x00"]; ok {
+			t.Error("the oldest search survived")
+		}
+		before := reg.count(fmt.Sprintf("list q%d|", marketplaceCacheSize+49))
+		if _, err := c.list(t.Context(), fmt.Sprintf("q%d", marketplaceCacheSize+49), ""); err != nil || reg.count(fmt.Sprintf("list q%d|", marketplaceCacheSize+49)) != before {
+			t.Errorf("the newest search was not cached: %v", err)
+		}
+		// Expired searches are dropped when a new one needs the room.
+		clk.advance(marketplaceTTL + time.Second)
+		if _, err := c.list(t.Context(), "fresh", ""); err != nil {
+			t.Fatal(err)
+		}
+		if n := len(c.lists); n != 1 {
+			t.Errorf("cached searches after expiry = %d, want 1", n)
+		}
+	})
+
 	t.Run("cache hit and expiry", func(t *testing.T) {
 		reg := &memPluginRegistry{versions: map[string][]kiosk.RegistryVersion{"acme.blog": {rel("v0.2.0", "v0.6.0")}, "acme.translate": {rel("v0.1.1", "v0.6.0")}}}
 		clk := &testClock{now: clock.Now()}