feat(memory): add Nowledge Mem provider integration

Add a new memory provider that delegates to a local Nowledge Mem instance
for memory storage, retrieval, and knowledge graph building.

Key design decisions:
- User messages tagged as [DisplayName], bot messages as [我]
- Per-message display name parsed from YAML front-matter headers
- Let Nowledge Mem handle entity extraction and graph building
- 6-way hybrid search (semantic + full-text + entity + community + label + graph)

New files:
- internal/memory/adapters/nowledgemem/client.go (REST API client)
- internal/memory/adapters/nowledgemem/nowledgemem.go (Provider impl)
- docs/nowledge-mem.md (design document with research and decisions)

Modified: types.go, service.go, serve.go (provider registration),
frontend (add-memory-provider.vue, types.gen.ts, i18n locales)

apps/web/src/i18n/locales/en.json

@@ -382,7 +382,8 @@
     "providerNames": {
       "builtin": "Built-in",
       "mem0": "Mem0",
-      "openviking": "OpenViking"
+      "openviking": "OpenViking",
+      "nowledgemem": "Nowledge Mem"
     }
   },
   "speech": {

apps/web/src/i18n/locales/zh.json

@@ -378,7 +378,8 @@
     "providerNames": {
       "builtin": "内置",
       "mem0": "Mem0",
-      "openviking": "OpenViking"
+      "openviking": "OpenViking",
+      "nowledgemem": "Nowledge Mem"
     }
   },
   "speech": {

apps/web/src/pages/memory/components/add-memory-provider.vue

@@ -40,6 +40,9 @@
                 <SelectItem value="openviking">
                   {{ $t('memory.providerNames.openviking') }}
                 </SelectItem>
+                <SelectItem value="nowledgemem">
+                  {{ $t('memory.providerNames.nowledgemem') }}
+                </SelectItem>
               </SelectGroup>
             </SelectContent>
           </Select>