feat(pipeline): update system prompt for new LLM JSON contract (no slugs)

- Change prompt to reflect new output format: title, type, subtype, domain, content
- Remove slug/path generation responsibility from LLM — pipeline now handles it
- Wikilinks change from [[slug|Display Name]] to [[Display Name]] only
- LLM no longer includes frontmatter or paths in output

docs(schema): update LLM output format and wikilink convention for Level 3

- Specify JSON schema: title, type, subtype, domain, content fields
- Remove frontmatter requirements from schema output (handled by pipeline)
- Simplify wikilink format to [[Display Name]] — no slug or pipe
- Pipeline now responsible for slug generation and frontmatter construction

These changes shift slug/frontmatter generation from LLM to pipeline,
reducing cognitive load on the model and improving control over output.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ingestion/internal/pipeline/prompt.go

@@ -12,12 +12,15 @@ import (
 const systemPrompt = `You are a wiki agent. Read the source material and produce structured wiki pages following the schema provided.
 
 Output ONLY a valid JSON array — no markdown fences, no other text before or after.
-Each element must have:
-  "path"    — relative path within the wiki, e.g. "wiki/sources/foo.md"
-  "content" — full markdown content of the page including YAML frontmatter
+Each element must have exactly these fields:
+  "title"   — exact page title (e.g. "FinBERT", "Ryan Singer", "Shape Up")
+  "type"    — exactly one of: "source", "concept", "entity"
+  "subtype" — for source: article|pdf|book|video|note|project; for entity: person|company|tool|model|framework|technology; omit for concept
+  "domain"  — one of the domains in the schema (omit if none fits)
+  "content" — Markdown body only — NO frontmatter, NO path, NO slug
 
-Follow the schema strictly: correct frontmatter fields, wikilinks as [[slug|Display Text]],
-dates in YYYY-MM-DD format, and paraphrase rather than quoting verbatim.`
+Wikilinks in content: [[Display Name]] — just the display name, no slug, no pipe separator.
+Only link to pages listed in the inventory or pages you are creating in this response.`
 
 // BuildPrompt constructs the user prompt for a single chunk.
 func BuildPrompt(schema, source, content string, inventory map[wiki.PageType][]wiki.Entry) string {
@@ -30,7 +33,7 @@ func BuildPrompt(schema, source, content string, inventory map[wiki.PageType][]w
 	sb.WriteString("\n\n")
 
 	sb.WriteString("## Existing wiki pages\n\n")
-	sb.WriteString("Link ONLY to pages in this inventory or pages you are creating in this response.\n\n")
+	sb.WriteString("Reference these pages by display name only — [[Display Name]] — in your content.\n\n")
 
 	for _, pt := range []wiki.PageType{wiki.PageTypeConcept, wiki.PageTypeEntity, wiki.PageTypeSource} {
 		entries := inventory[pt]
@@ -39,19 +42,19 @@ func BuildPrompt(schema, source, content string, inventory map[wiki.PageType][]w
 			fmt.Fprintf(&sb, "%s — (none yet)\n\n", label)
 			continue
 		}
-		fmt.Fprintf(&sb, "%s — link ONLY under the matching section:\n", label)
+		fmt.Fprintf(&sb, "%s:\n", label)
 		for _, e := range entries {
-			fmt.Fprintf(&sb, "  - [[%s|%s]]\n", e.Slug, e.Title)
+			fmt.Fprintf(&sb, "  - %s\n", e.Title)
 		}
 		sb.WriteString("\n")
 	}
 
 	sb.WriteString("## Non-negotiable rules\n\n")
 	sb.WriteString("1. Output ONLY a valid JSON array — no prose, no fences.\n")
-	sb.WriteString("2. Slugs are kebab-case: lowercase, spaces→hyphens, no special chars.\n")
-	sb.WriteString("3. Wikilinks: [[slug|Display Text]] — the pipe is required.\n")
-	sb.WriteString("4. Section links must match their section type.\n")
-	sb.WriteString("5. One source page per book — update it if inventory shows it exists.\n\n")
+	sb.WriteString("2. Fields: title, type, subtype (if applicable), domain (if applicable), content.\n")
+	sb.WriteString("3. Wikilinks: [[Display Name]] — no slug, no pipe. The pipeline handles slugs.\n")
+	sb.WriteString("4. Section links must match their section type (Related Concepts → concepts only, etc.).\n")
+	sb.WriteString("5. One source page per book — if inventory shows it exists, return it as an UPDATE.\n\n")
 
 	fmt.Fprintf(&sb, "## Source: %s\n\n", source)
 	sb.WriteString(content)