docs: refresh references stale since the v3 pipeline landed

Commit a488e1904 deleted mem0/graphs/ and mem0-ts/src/oss/src/graphs/ when the
v3 pipeline landed, and 3f717e545 reframed the docs as Platform-only, but the
agent-facing context files were never updated. Agents reading them still
believe OSS graph memory exists and propose graph_store config that cannot work.

- AGENTS.md: drop graphs/ from the directory map and dependency tree, correct
  the provider table (4 categories, not 5; LLMs 24->18, vector stores 30->25,
  embeddings 15->12), and rewrite the Graph Memory section as Platform-only
- skills: replace the OSS graph-memory prompt example and stop indexing
  /open-source/features/graph-memory, which 404s; also fix four other
  SECTION_MAP paths that no longer resolve
- mem0/exceptions.py: DependencyError example referenced kuzu/graph_store
- tests/test_telemetry.py: drop four mock_memory.config.graph_store lines;
  graph_store is not a MemoryConfig field and telemetry never reads it
- CONTRIBUTING.md: add the three missing release tag prefixes (opencode-v*,
  pi-agent-v*, n8n-nodes-mem0-v*) and note Zapier deploys off-registry

integrations/mem0-plugin/skills/mem0/README.md

@@ -40,7 +40,7 @@ After installing, just ask Claude:
 - "Add memory to my chatbot"
 - "Help me search user memories with filters"
 - "Integrate mem0 with my LangChain app"
-- "Add graph memory to track entity relationships"
+- "Migrate my app from mem0 v2 to v3"
 
 ## What's Inside
 
@@ -56,7 +56,7 @@ skills/mem0/
     ├── sdk-guide.md            # All SDK methods (Python + TypeScript)
     ├── api-reference.md        # REST endpoints, filters, memory object
     ├── architecture.md         # Processing pipeline, lifecycle, scoping, performance
-    ├── features.md             # Retrieval, graph, categories, MCP, webhooks, multimodal
+    ├── features.md             # Retrieval, entity linking, categories, MCP, webhooks, multimodal
     ├── integration-patterns.md # LangChain, CrewAI, Vercel AI, LangGraph, LlamaIndex, etc.
     └── use-cases.md            # 7 real-world patterns with Python + TypeScript code
 ```

integrations/mem0-plugin/skills/mem0/scripts/mem0_doc_search.py

@@ -36,9 +36,8 @@ SECTION_MAP = {
     "platform": [
         "/platform/overview",
         "/platform/quickstart",
-        "/platform/features",
         "/platform/features/graph-memory",
-        "/platform/features/selective-memory",
+        "/platform/features/advanced-retrieval",
         "/platform/features/custom-categories",
         "/platform/features/v2-memory-filters",
         "/platform/features/async-client",
@@ -57,10 +56,10 @@ SECTION_MAP = {
         "/open-source/overview",
         "/open-source/python-quickstart",
         "/open-source/node-quickstart",
-        "/open-source/features",
-        "/open-source/features/graph-memory",
+        "/open-source/features/overview",
         "/open-source/features/rest-api",
-        "/open-source/configure-components",
+        "/open-source/features/metadata-filtering",
+        "/open-source/configuration",
     ],
     "sdks": [
         "/sdks/python",