feat(search): Phase 627 search hub depth (v0.8.590)

Extend search hub/panel live regions with active channel context and mesh
notes; tighten search-errors reaction bleed exclusion; refresh composer
search hints for hub and panel; platform guild.search.cache/mesh spans
include activeChannelId; agentctl and phase627 smoke bundle.

index.js

@@ -1938,7 +1938,9 @@ class PearcordPlatform extends EventEmitter {
           count: this._cachedSearchResults.length,
           cached: true,
           scope: this._searchScope,
-          guildId: this.guild?.guild?.id || null
+          guildId: this.guild?.guild?.id || null,
+          activeChannelId: this.activeChannelId,
+          guildCount: (this.guilds || []).length
         })
         return this._cachedSearchResults
       }
@@ -2056,7 +2058,9 @@ class PearcordPlatform extends EventEmitter {
           spanKind: 'guild.search.mesh',
           meshHitCount: out.meshHitCount || 0,
           localHitCount: out.localHitCount || 0,
-          mergedCount: out.hits?.length || 0
+          mergedCount: out.hits?.length || 0,
+          activeChannelId: this.activeChannelId,
+          guildCount: (this.guilds || []).length
         })
       }
       this._commitSearchCache(cacheKey, out.hits)
@@ -2165,7 +2169,9 @@ class PearcordPlatform extends EventEmitter {
           spanKind: 'guild.search.mesh',
           meshHitCount: out.meshHitCount || 0,
           localHitCount: out.localHitCount || 0,
-          mergedCount: filtered?.length || 0
+          mergedCount: filtered?.length || 0,
+          activeChannelId: this.activeChannelId,
+          guildCount: (this.guilds || []).length
         })
       }
       this._commitSearchCache(cacheKey, filtered)