Remove legacy shared prompt package and update docs

docs/internal/modules.md

@@ -41,10 +41,12 @@ request. Prompt metadata hashes remain based on prompt asset source, not
 rendered reference bytes.
 
 LLM-backed modules own Scriptorium prompt definitions and response schemas in
-their embedded assets. Module contracts should expose prompt IDs, versions,
-input material names, and non-secret prompt/schema hashes through manifest
-metadata; they should not expose Scriptorium public types through chunk,
-extract, or normalize contracts.
+their embedded assets. Module-owned prompts live under each module's shallow
+`assets/prompts` tree and schemas live under `assets/schemas`. Shared reusable
+prompt fragments live under `internal/modules/sharedassets`. Module contracts
+should expose prompt IDs, versions, input material names, and non-secret
+prompt/schema hashes through manifest metadata; they should not expose
+Scriptorium public types through chunk, extract, or normalize contracts.
 
 Chunk modules receive the structured LLM client, configured Scriptorium profile
 ID, prompt session ID, and raw source input material through
@@ -104,6 +106,10 @@ prompt ID, prompt version, transcript input material, response schema, and
 session ID to the runtime; validates model-authored source-unit boundaries; and
 converts each scene into a deterministic source chunk.
 
+Its prompt definition lives under `assets/prompts` and its schema under
+`assets/schemas`. Shared reusable prompt fragments are provided by
+`internal/modules/sharedassets`.
+
 Requires:
 
 - `source.transcript`
@@ -138,6 +144,10 @@ input materials, response schema, and session ID to the runtime; converts
 spell-cast responses into artifact candidates; and supplies deterministic
 validators.
 
+Its prompt definition lives under `assets/prompts` and its schema under
+`assets/schemas`. Shared reusable prompt fragments are provided by
+`internal/modules/sharedassets`.
+
 Requires:
 
 - `chunks`