feat: harden notification stack and switch logging selectors to icon grid

Notifications:
- Add shared http_base, redact, and SSRF hardening modules
- Refactor dispatcher, queue, receiver and per-provider clients
  (telegram, discord, email, matrix, ntfy, slack, webhook) to use
  the shared base, with bounded queue and redacted error logs
- Tests for ssrf, redact, http_base, queue bounds, dispatcher
  aggregation, telegram media partition, email and matrix clients

Frontend:
- Settings: log level / log format selectors now use IconGridSelect
  with per-option icons and i18n descriptions
- Minor providers page and entity-cache store updates

Tooling:
- Document code-review-graph MCP usage in CLAUDE.md
- Ignore .code-review-graph/, register .mcp.json

CLAUDE.md

@@ -43,3 +43,42 @@ Detailed context is split into focused documents under `.claude/docs/`. Read the
     - Notification preview sample: `packages/server/src/notify_bridge_server/services/sample_context.py` (`_SAMPLE_CONTEXT`)
     - Command preview sample: `packages/server/src/notify_bridge_server/api/command_template_configs.py` (`sample_ctx` in `preview_raw`)
     - Runtime validator whitelist: `packages/core/src/notify_bridge_core/templates/validator.py`
+
+<!-- code-review-graph MCP tools -->
+## MCP Tools: code-review-graph
+
+**IMPORTANT: This project has a knowledge graph. ALWAYS use the
+code-review-graph MCP tools BEFORE using Grep/Glob/Read to explore
+the codebase.** The graph is faster, cheaper (fewer tokens), and gives
+you structural context (callers, dependents, test coverage) that file
+scanning cannot.
+
+### When to use graph tools FIRST
+
+- **Exploring code**: `semantic_search_nodes` or `query_graph` instead of Grep
+- **Understanding impact**: `get_impact_radius` instead of manually tracing imports
+- **Code review**: `detect_changes` + `get_review_context` instead of reading entire files
+- **Finding relationships**: `query_graph` with callers_of/callees_of/imports_of/tests_for
+- **Architecture questions**: `get_architecture_overview` + `list_communities`
+
+Fall back to Grep/Glob/Read **only** when the graph doesn't cover what you need.
+
+### Key Tools
+
+| Tool | Use when |
+|------|----------|
+| `detect_changes` | Reviewing code changes — gives risk-scored analysis |
+| `get_review_context` | Need source snippets for review — token-efficient |
+| `get_impact_radius` | Understanding blast radius of a change |
+| `get_affected_flows` | Finding which execution paths are impacted |
+| `query_graph` | Tracing callers, callees, imports, tests, dependencies |
+| `semantic_search_nodes` | Finding functions/classes by name or keyword |
+| `get_architecture_overview` | Understanding high-level codebase structure |
+| `refactor_tool` | Planning renames, finding dead code |
+
+### Workflow
+
+1. The graph auto-updates on file changes (via hooks).
+2. Use `detect_changes` for code review.
+3. Use `get_affected_flows` to understand impact.
+4. Use `query_graph` pattern="tests_for" to check coverage.