feat: EditorRuntimeActor - 三层缓存/delta/事件架构

Phase A — EditorRuntimeActor 内存缓存层
- 新增 editor_actor.rs: EditorBlockDocument 内存态 + apply_command + load_or_init
- block.rs 四个写工具（replace/insert/delete/move）接入 actor 路径
- editor_actor feature flag（MNOTE_WEB_ENABLE_EDITOR_ACTOR=true 默认开启）
- bridge-runtime 三个核心函数公开化
- rust-toolchain: 1.89 → stable（修复 spike WASM 编译阻塞）

Phase B — 编辑器增量 delta channel
- BlockDelta/DeltaOperation 类型 + actor.build_block_delta()
- leptos-tiptap spike: mnote:editor:block-delta CustomEvent 监听 + JSON patch
- DocumentAiAgentPanel: 拦截 blockDelta → window dispatchEvent
- 工具响应含 blockDelta 字段供前端消费

Phase C — 事件 stream delta
- broadcast channel 在 AppState/actor/SSE 三层贯通
- tree_events SSE 端点发 block.delta 事件
- 旧客户端降级兼容

环境修复
- rustc recursion_limit = 1024（修复 Leptos SSR 类型深度溢出）
- run-convex-deploy.js（封装 Convex function 部署到本地后端 3210）

ref: design/07-ai/process/7-13-page-block-editor-runtime-actor-v1.md

rust/crates/mnote-web/src/routes/local_folder_source.rs

@@ -8,6 +8,7 @@ use crate::routes::local_markdown_parser::{
 };
 use crate::routes::snapshot_support::ProjectionSnapshot;
 use axum::http::StatusCode;
+use bridge_runtime::project_legacy_content_to_block_document;
 use serde::{Deserialize, Serialize};
 use serde_json::{json, Map, Value};
 use std::cmp::Ordering;
@@ -306,6 +307,10 @@ pub fn resolve_local_markdown_page_aggregate(
         .count() as u64;
     let read_only = markdown_file.is_readonly;
 
+    let block_document =
+        project_legacy_content_to_block_document(document_id, &content, &Value::Number(0.into()))
+            .map_err(|error| WebError::internal(format!("{error:?}")))?;
+
     Ok(PageAggregate {
         schema: PageAggregate::SCHEMA.into(),
         projection_version: PageAggregate::VERSION,
@@ -339,6 +344,9 @@ pub fn resolve_local_markdown_page_aggregate(
                 document_id,
                 &markdown_file.path,
             )?),
+            block_document,
+            block_projection_version: 1,
+            projection_source: "local_markdown.content".into(),
         },
         tree: PageTree { page_subtree },
         stats: PageStats {