Extract prompt sources and rendering internals

docs/internal/overview.md

@@ -15,10 +15,14 @@ contributor workflow and validation.
 | `internal/domain` | Defines internal framework values for requests, artifacts, prompt definitions, profiles, execution targets, rendering, generation, and validation. | [Domain declarations](../../internal/domain/domain.go) |
 | `internal/defaults` | Defines application-neutral framework constants and constructs the default execution target. It contains no CLI, server, or inbound HTTP limits. | [Framework defaults](../../internal/defaults/defaults.go) |
 | `internal/filecatalog` | Provides deterministic YAML discovery and path helpers for operating-system filesystems and `fs.FS` sources. | [File catalog](../../internal/filecatalog/catalog.go) |
+| `internal/promptdef` | Loads strictly decoded, validated prompt definitions from filesystem and `fs.FS` sources, including version selection and contained file-backed message content. | [Prompt-definition repository](../../internal/promptdef/filesystem_repository.go) |
+| `internal/profile` | Loads strictly decoded, validated execution profiles from filesystem and `fs.FS` sources and composes repositories with error-preserving fallback. | [Profile repositories](../../internal/profile/filesystem_repository.go) |
+| `internal/profile/builtin` | Embeds the built-in execution profile catalog and combines it with an optional primary repository. | [Built-in profile repository](../../internal/profile/builtin/repository.go) |
+| `internal/prompt` | Renders prompt messages from Go templates with artifact, variable, session, and cache-control data. | [Go-template renderer](../../internal/prompt/go_renderer.go) |
 
-These packages form the internal extraction foundation. Prompt and profile
-sources, rendering, artifact reading, validation, model clients, orchestration,
-and a usable public engine are not implemented in Promptkit yet.
+These packages provide the internal model, source, and rendering foundation.
+Artifact reading, output validation, model clients, orchestration, and a usable
+public engine are not implemented in Promptkit yet.
 
 ## Maintenance
 

docs/policy/architecture.md

@@ -16,19 +16,27 @@ The module root contains package `promptkit`, which is the public facade. It
 declares the module's public package boundary but does not yet provide a usable
 exported framework API.
 
-The implemented internal foundation consists of:
+The implemented internal components consist of:
 
 - `internal/domain`, which owns framework data values shared by later internal
   components;
 - `internal/defaults`, which owns application-neutral framework defaults and
   constructs the default execution target; and
 - `internal/filecatalog`, which discovers YAML files and provides source-path
-  helpers for filesystem and `fs.FS` consumers.
+  helpers for filesystem and `fs.FS` consumers;
+- `internal/promptdef`, which loads and validates prompt definitions from
+  filesystem and `fs.FS` sources;
+- `internal/profile`, which loads, validates, and overlays execution profiles
+  from filesystem and `fs.FS` sources;
+- `internal/profile/builtin`, which embeds the built-in execution profile
+  catalog; and
+- `internal/prompt`, which renders prompt messages from Go templates.
 
-`internal/defaults` depends on `internal/domain`; the file catalog is
-independent and uses only the standard library. Prompt and profile sources,
-rendering, artifact reading, validation, model clients, orchestration, and the
-public engine have not yet been extracted.
+The defaults and renderer depend on the domain model. Prompt-definition and
+profile repositories use the domain model, file catalog, and YAML decoder. The
+built-in profile repository supplies an embedded `fs.FS` to the profile
+package. Artifact reading, output validation, model clients, orchestration, and
+the public engine have not yet been extracted.
 
 Future framework extraction must follow this dependency direction: