feat: add ReactiveStatManager for markdown template support

Introduce ReactiveStatManager to allow dynamic stat replacement within
rendered markdown content. This component scans the article DOM for
`${key}` patterns and reactively updates them based on the journal
stream.

As part of this change, the SVG-based StatSheet system is removed in
favor of this more flexible text-based approach.

src/cli/completions/block-processor.ts

@@ -20,7 +20,6 @@ import {
   parseBlockAttrs,
   resolveBlockAs,
 } from "./block-scanner.js";
-import type { StatSheet } from "./types.js";
 
 // Re-export shared pieces for convenience
 export {
@@ -37,7 +36,6 @@ export {
 export interface ProcessedBlocks {
   stats: StatDef[];
   statTemplates: StatTemplate[];
-  statSheets: StatSheet[];
 }
 
 export interface BlockResult {
@@ -78,7 +76,6 @@ export function processBlocks(
   const blocks: ProcessedBlocks = {
     stats: [],
     statTemplates: [],
-    statSheets: [],
   };
 
   const stripped = content.replace(

src/cli/completions/index.ts

@@ -14,7 +14,6 @@ export type {
   SparkTableCompletion,
   StatDef,
   StatTemplate,
-  StatSheet,
 } from "./types.js";
 
 /**
@@ -43,6 +42,5 @@ export function scanCompletions(
     sparkTables,
     stats: blocks.stats,
     statTemplates: blocks.statTemplates,
-    statSheets: blocks.statSheets,
   };
 }

src/cli/completions/types.ts

@@ -6,18 +6,6 @@ import type { StatDef, StatTemplate } from "./stat-parser.js";
 
 export type { StatDef, StatTemplate };
 
-/** A stat sheet discovered from a *.sheet.svg file */
-export interface StatSheet {
-  /** Unique id — filename sans .sheet.svg */
-  id: string;
-  /** Display label — from <title> or derived from filename */
-  label: string;
-  /** Raw SVG content */
-  svg: string;
-  /** Source file path for attribution */
-  source: string;
-}
-
 /** A single dice expression found in a markdown file */
 export interface DiceCompletion {
   /** Display text shown in the dropdown */
@@ -62,7 +50,6 @@ export interface CompletionsPayload {
   sparkTables: SparkTableCompletion[];
   stats: StatDef[];
   statTemplates: StatTemplate[];
-  statSheets: StatSheet[];
 }
 
 /**