feat(ai): SSE streaming for foreground Mission Runner

Enable real-time token streaming during the planner "calling-llm" phase
so the user sees live progress ("empfange Plan… 128 tokens") instead of
a static spinner. The parser still receives the full text once complete —
no partial-JSON risk.

Changes:
- Extract shared SSE parser from playground into @mana/shared-llm/sse-parser
- remote.ts: use stream:true when onToken callback is provided
- AiPlanInput: add optional onToken field (shared-ai)
- ai-plan task: pass onToken through to backend.generate()
- runner.ts: throttled (500ms) phaseDetail updates during streaming
- Playground: refactored to use shared SSE parser

Also includes: AI agent architecture comparison report (docs/reports/)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/shared-llm/package.json

@@ -7,7 +7,8 @@
 	"main": "./src/index.ts",
 	"types": "./src/index.ts",
 	"exports": {
-		".": "./src/index.ts"
+		".": "./src/index.ts",
+		"./sse-parser": "./src/sse-parser.ts"
 	},
 	"scripts": {
 		"type-check": "tsc --noEmit",