Phase 3: LLM grammar checkpoint

Backend (internal/llm): backend-agnostic LLMClient interface + factory
with vLLM (OpenAI-compat) and Ollama (native) clients, each Complete +
Stream. prompts.go holds the checkpoint and Ask Petal templates;
checkpoint.go salvages JSON from model output (brace-matched), enforces a
per-doc 30s RateLimiter, and truncates the doc to a latency cap.

internal/suggestions: POST /api/docs/:id/check runs a checkpoint and
replaces the doc's pending suggestions in one tx (accepted/rejected kept
as history); GET /api/docs/:id/suggestions lists pending;
POST /api/suggestions/:id/{accept,dismiss} resolves one. Throttled checks
return the current set rather than erroring.

Frontend: useCheckpoint (4s debounce, loads existing on open, stale-guard
tokens); SuggestionHighlight renders ProseMirror decorations re-anchored
by the `original` string on every doc change (not stored marks), with
precise textblock-offset→PM-position mapping; SuggestionCard shows the
type tag + diff + explanation and applies the replacement in-editor on
accept; breathing rose checkpoint dot in the StatusBar; fade-float +
breathe animations.

Tests: llm parse/rate-limit/truncate; suggestions full flow + rate-limit
over httptest with a stub client. Smoke-tested end-to-end against a fake
vLLM endpoint (anchoring verified) and the LLM-unreachable 502 path.

Claude-Session: https://claude.ai/code/session_016Yr6jELuRc7hyzYLccQKZd

cmd/server/main.go

@@ -13,6 +13,8 @@ import (
 	"gitea.parodia.dev/drwily/petal/internal/config"
 	"gitea.parodia.dev/drwily/petal/internal/db"
 	"gitea.parodia.dev/drwily/petal/internal/docs"
+	"gitea.parodia.dev/drwily/petal/internal/llm"
+	"gitea.parodia.dev/drwily/petal/internal/suggestions"
 	"gitea.parodia.dev/drwily/petal/web"
 )
 
@@ -38,7 +40,17 @@ func main() {
 			_, _ = w.Write([]byte(`{"status":"ok"}`))
 		})
 
-		api.Mount("/docs", docs.New(database).Routes())
+		llmClient := llm.NewLLMClient(cfg)
+		sug := suggestions.New(database, llmClient)
+
+		// Document CRUD plus the doc-scoped checkpoint/list suggestion routes,
+		// both under /api/docs.
+		docsRouter := docs.New(database).Routes()
+		sug.RegisterDocRoutes(docsRouter)
+		api.Mount("/docs", docsRouter)
+
+		// Per-suggestion actions (accept/dismiss) under /api/suggestions.
+		api.Mount("/suggestions", sug.Routes())
 	})
 
 	// Everything else: serve the embedded SPA (with index.html fallback for client routing).