fix(api-docs): generate request bodies for all encodings (#6296)

* fix(api-docs): generate request bodies for all encodings

The OpenAPI generator only recognized generic body parameters, so JSON, form, and multipart declarations disappeared into empty application/json objects. Generate the declared media type and schema, preserve optionality and conditional requirements, and encode repeated form arrays the way Gin expects. Correct the request metadata exposed by the complete schemas and keep the panel and docs specifications synchronized.

* fix(api-docs): align alternative request schemas

Keep non-empty constraints on the selected request-body alternative without rejecting empty values for the alternatives that panel requests also include. Allow null client IP lists because model serialization emits them while cleared rows await pruning.

* fix(api-docs): send object urlencoded fields as JSON, document the inbound update body

Four defects the request-body rework exposed or left behind:

- An object-typed field in an x-www-form-urlencoded body got no encoding
  entry, so OpenAPI 3.0 serialized it form-style. Swagger "Try it out"
  and generated clients sent memberWeights=3&memberWeights=0.2 to
  /panel/api/sub-balancers, and parseSubBalancerForm json.Unmarshals the
  raw field, so every such call failed with "invalid memberWeights".
  Emit encoding.<name>.contentType = application/json instead.
- bodyRequiredOneOf names were never checked against the declared body
  params: a typo emitted an anyOf branch requiring a property that does
  not exist — unsatisfiable — and make gen still passed. Throw now, and
  extend the requestSchema guard to reject bodyRequiredOneOf as well.
- /panel/api/inbounds/update/:id advertised no request body although its
  own summary says the shape mirrors /add and updateInbound binds one.
  Both entries now share an inboundBody const so they cannot drift.
- The mixed-locations error was the only buildOperation throw without
  the method and path, aborting make gen without naming the offender.

Regenerated frontend/public/openapi.json and copied it to
docs/public/openapi.json. No MDX regeneration: no summary changed.

---------

Co-authored-by: Sanaei <ho3ein.sanaei@gmail.com>

docs/content/docs/en/reference/api/server.mdx

@@ -123,9 +123,9 @@ _openapi:
         dev release. Only effective on dev builds.
       url: '#toggle-the-panel-update-channel-between-stable-and-the-rolling-per-commit-dev-release-only-effective-on-dev-builds'
     - depth: 2
-      title: Refresh the default GeoIP / GeoSite data files. Body can include a
-        fileName, or use the /:fileName variant.
-      url: '#refresh-the-default-geoip--geosite-data-files-body-can-include-a-filename-or-use-the-filename-variant'
+      title: Refresh the default GeoIP / GeoSite data files. Use the /:fileName
+        variant to update one file.
+      url: '#refresh-the-default-geoip--geosite-data-files-use-the-filename-variant-to-update-one-file'
     - depth: 2
       title: Refresh a single Geo file by filename (e.g. geoip.dat, geosite.dat).
       url: '#refresh-a-single-geo-file-by-filename-eg-geoipdat-geositedat'
@@ -271,9 +271,9 @@ _openapi:
       - content: Toggle the panel update channel between stable and the rolling
           per-commit dev release. Only effective on dev builds.
         id: toggle-the-panel-update-channel-between-stable-and-the-rolling-per-commit-dev-release-only-effective-on-dev-builds
-      - content: Refresh the default GeoIP / GeoSite data files. Body can include a
-          fileName, or use the /:fileName variant.
-        id: refresh-the-default-geoip--geosite-data-files-body-can-include-a-filename-or-use-the-filename-variant
+      - content: Refresh the default GeoIP / GeoSite data files. Use the /:fileName
+          variant to update one file.
+        id: refresh-the-default-geoip--geosite-data-files-use-the-filename-variant-to-update-one-file
       - content: Refresh a single Geo file by filename (e.g. geoip.dat, geosite.dat).
         id: refresh-a-single-geo-file-by-filename-eg-geoipdat-geositedat
       - content: Return the last N lines of the panel’s own log.

docs/content/docs/en/reference/api/subscription-balancers.mdx

@@ -18,9 +18,9 @@ _openapi:
       url: '#create-a-subscription-balancer-it-appears-in-the-json-subscription-of-every-client-that-sits-on-at-least-one-selected-inbound'
     - depth: 2
       title: Update a balancer by id. Accepts the same form fields as create (full-row
-        update, including the enabled toggle); omitting memberWeights clears
-        stored weights.
-      url: '#update-a-balancer-by-id-accepts-the-same-form-fields-as-create-full-row-update-including-the-enabled-toggle-omitting-memberweights-clears-stored-weights'
+        update); omitting memberWeights clears stored weights, while omitting
+        enabled keeps its current value.
+      url: '#update-a-balancer-by-id-accepts-the-same-form-fields-as-create-full-row-update-omitting-memberweights-clears-stored-weights-while-omitting-enabled-keeps-its-current-value'
     - depth: 2
       title: Delete a balancer by id.
       url: '#delete-a-balancer-by-id'
@@ -36,9 +36,9 @@ _openapi:
           every client that sits on at least one selected inbound.
         id: create-a-subscription-balancer-it-appears-in-the-json-subscription-of-every-client-that-sits-on-at-least-one-selected-inbound
       - content: Update a balancer by id. Accepts the same form fields as create
-          (full-row update, including the enabled toggle); omitting
-          memberWeights clears stored weights.
-        id: update-a-balancer-by-id-accepts-the-same-form-fields-as-create-full-row-update-including-the-enabled-toggle-omitting-memberweights-clears-stored-weights
+          (full-row update); omitting memberWeights clears stored weights, while
+          omitting enabled keeps its current value.
+        id: update-a-balancer-by-id-accepts-the-same-form-fields-as-create-full-row-update-omitting-memberweights-clears-stored-weights-while-omitting-enabled-keeps-its-current-value
       - content: Delete a balancer by id.
         id: delete-a-balancer-by-id
       - content: Delete a balancer by id (POST alias of DELETE for clients that cannot