feat(safety): report, block and hide chat lines (MODULE_API 1.21.0)

USER_SAFETY.md step 3, the module half of report, block and hide.

- server/safety.js registers the rust.chat report target (snapshot for one
  reader, null when they could not have seen the line; staff's hide and
  unhide) and the steam game identity (ownersOf from rust_account_links).
- The events feed filters chat per reader, in the query: lines from a
  blocked account's Steam ids, the reader's unlinked Steam-ID blocks and the
  lines they hid. Signed-in readers get canBlock on each chat line (false for
  their own and for staff-linked players). Lines staff hid for everyone are
  left out for everyone but staff, who get them with hidden: true.
- rust_events gains hidden_at and hidden_by (ALTER ... IF NOT EXISTS).
- POST /admin/rust/chat/:id/hide and /unhide (admin, moderator), logged.
- The feed's chat lines get a menu: Report, Hide for me, Block player,
  and for staff Hide for everyone / Show to everyone again.
- coreApi ^1.21.0; ci/core-ref.json pinned to the website#233 merge;
  routes.manifest.json and swagger-fragment.json regenerated.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01E14m6SuuY6i1vASFeGDBeY

swagger-fragment.json

@@ -1,5 +1,61 @@
 {
   "paths": {
+    "/api/v1/admin/rust/chat/{id}/hide": {
+      "post": {
+        "tags": [
+          "Admin · Rust"
+        ],
+        "summary": "Hide a chat line for everyone",
+        "description": "Staff’s hide for everyone (USER_SAFETY.md S10): the line leaves the public feed for everybody but staff, who still get it with `hidden: true`. The same flag core’s Reports queue sets through the `rust.chat` report target. Hiding a hidden line changes nothing. Recorded in the activity log. Admins and moderators.",
+        "parameters": [
+          {
+            "name": "id",
+            "in": "path",
+            "required": true,
+            "schema": {
+              "type": "integer"
+            },
+            "description": "The chat line’s event id"
+          }
+        ],
+        "responses": {
+          "204": {
+            "description": "Hidden"
+          },
+          "404": {
+            "description": "No such chat line"
+          }
+        }
+      }
+    },
+    "/api/v1/admin/rust/chat/{id}/unhide": {
+      "post": {
+        "tags": [
+          "Admin · Rust"
+        ],
+        "summary": "Show a hidden chat line again",
+        "description": "Undoes a hide for everyone, whether it was made here or from the Reports queue. Recorded in the activity log. Admins and moderators.",
+        "parameters": [
+          {
+            "name": "id",
+            "in": "path",
+            "required": true,
+            "schema": {
+              "type": "integer"
+            },
+            "description": "The chat line’s event id"
+          }
+        ],
+        "responses": {
+          "204": {
+            "description": "Shown again"
+          },
+          "404": {
+            "description": "No such chat line"
+          }
+        }
+      }
+    },
     "/api/v1/admin/rust/config/{serverId}/file": {
       "get": {
         "tags": [
@@ -3203,7 +3259,7 @@
           "Public · Rust"
         ],
         "summary": "Recent events on one Rust server",
-        "description": "The killfeed and everything else public that happened on a server, newest first. Narrow with `kind` (comma-separated) and `wipe`. Only publicly classified kinds are ever returned — moderation events, login attempts and anything carrying an IP address are stored but never served here. Kinds that name a player who was on the server (connects, respawns, deaths, chat, tallies) are served only to viewers inside the operator’s presence audience, which defaults to staff; `presenceHidden` says when they were withheld. Rust’s own world events (protocol 14, PLAN_REDESIGNS §14.3.1) arrive as `world.event` with `event` naming which of 24: they are public, with a `grid` worked out from the map, but a player’s `name` (and the names in `credited`) only for the presence audience, a Steam id and a position only for staff, and a type this build does not know only for staff. A downed patrol helicopter, Chinook or Bradley carries `credited` and `creditedCount` by the server’s `creditRule` as it was when the event arrived, so a line keeps naming whom the Rotorbane and Tankbreaker counts credited after the rule changes. A frame with a `weapon` (the held entity’s short prefab name, which the title lists count by) also carries `weaponName`, what a page should print: the game’s own name for a ranged weapon, or the prefab name as words with its `.entity` ending dropped.",
+        "description": "The killfeed and everything else public that happened on a server, newest first. Narrow with `kind` (comma-separated) and `wipe`. Only publicly classified kinds are ever returned — moderation events, login attempts and anything carrying an IP address are stored but never served here. Kinds that name a player who was on the server (connects, respawns, deaths, chat, tallies) are served only to viewers inside the operator’s presence audience, which defaults to staff; `presenceHidden` says when they were withheld. Rust’s own world events (protocol 14, PLAN_REDESIGNS §14.3.1) arrive as `world.event` with `event` naming which of 24: they are public, with a `grid` worked out from the map, but a player’s `name` (and the names in `credited`) only for the presence audience, a Steam id and a position only for staff, and a type this build does not know only for staff. A downed patrol helicopter, Chinook or Bradley carries `credited` and `creditedCount` by the server’s `creditRule` as it was when the event arrived, so a line keeps naming whom the Rotorbane and Tankbreaker counts credited after the rule changes. A frame with a `weapon` (the held entity’s short prefab name, which the title lists count by) also carries `weaponName`, what a page should print: the game’s own name for a ranged weapon, or the prefab name as words with its `.entity` ending dropped. Chat is read for each reader (USER_SAFETY.md §4.2): a signed-in reader does not get the lines of a player they blocked (by the player’s linked account, or by Steam id when there is none) or lines they hid for themselves, and each `player.chat` row carries `canBlock` — false for their own lines and for a player linked to a staff account. A line staff hid for everyone is left out for everybody but staff, who get it with `hidden: true`.",
         "parameters": [
           {
             "name": "id",