Normalize internal component documentation

docs/internal/state.md

@@ -1,55 +1,54 @@
-# Destination State
+# Destination State Internals
+
+Audience: developers and LLM coding agents changing `internal/state`.
 
 ## Purpose
 
-`internal/state` parses, validates, writes, and compares `.distributor.json` destination state.
+`internal/state` parses, validates, serializes, and compares `.distributor.json` destination state.
 
-## Inputs and outputs
+## Inputs And Outputs
 
-Input is JSON destination state plus the current source manifest, pipeline id, destination id, and whether the destination path has unmanaged content. Output is a deterministic comparison outcome and reason.
-
-## State behavior
-
-`.distributor.json` requires:
-
-- `schema_version: 1`
-- `pipeline_id`
-- `destination_id`
-- `published_at`
-- `source.manifest`
-- `outputs`
-
-`distributor_version` is optional diagnostic metadata. `links` is optional URL metadata. `published_at` parses as RFC3339 and distributor-written state serializes it as RFC3339 UTC.
-
-The embedded `source.manifest` is validated with the same source manifest rules used by `internal/bundle`.
-
-## Outputs
-
-Each output records `path`, `kind`, `source_path`, `sha256`, and `size`. Supported output kinds are `source` and `generated`. Generated outputs require `transform`. Outputs may record `url` when the destination has link generation configured.
-
-The optional top-level `links.primary_url` records the selected primary URL for the published destination bundle. It is omitted when link generation is not configured or when the destination primary policy has no matching output.
-
-## Comparison
-
-Comparison outcomes cover absent destination state, unmanaged destination content, invalid state, pipeline or destination mismatch, same source manifest, older destination source, newer destination source, same-created digest conflict, and different source id conflict.
-
-## Failure behavior
-
-Invalid JSON, invalid state schema, invalid embedded source manifests, unsafe output paths, invalid stored URLs, unsupported output kinds, missing generated-output transform names, and mismatched pipeline or destination ids produce comparison outcomes that publish planning can turn into fail actions. Supported identity and source-manifest conflicts can become forced replacement only when publish planning receives explicit force and compatible transfer policy.
+Inputs are destination state JSON, constructed state values, current source manifest, pipeline id, destination id, and whether the destination path has content without state. Outputs are validated state values, JSON bytes, comparison outcomes, and human-readable reasons.
 
 ## Boundaries
 
-This package does not publish files, delete files, inspect storage backends, or choose transfer policy actions. Publish planning consumes these comparison outcomes later.
+The package does not inspect storage backends, mutate files, choose transfer policy, build publish outputs, generate URLs, or parse config. Publish planning consumes state comparison outcomes.
 
-## Tests
+The external destination state contract is documented in `docs/integrations/destination-state.md`.
 
-Before changing destination state behavior, inspect tests under `internal/state`.
+## Config Fields Used
 
-## Invariants
+None directly. Destination ids, pipeline ids, and link URLs originate from config but are supplied as values by callers.
+
+## Adapters Used
+
+None.
+
+## State And Manifest Behavior
+
+`.distributor.json` schema version is `1`. Required fields are `pipeline_id`, `destination_id`, `published_at`, `source.manifest`, and `outputs`. `distributor_version` and `links` are optional.
+
+Embedded source manifests are parsed and validated through `internal/bundle`, which delegates source manifest semantics to `pkg/bundle`. Output records require clean paths, `source` or `generated` kind, valid source paths, lowercase SHA-256 digests, non-negative sizes, and transform ids for generated outputs. Stored URLs must pass `internal/link` validation.
+
+## Skip And Resume Behavior
+
+Comparison is pure. It returns outcomes for absent state, unmanaged content, invalid state, pipeline/destination mismatch, same source manifest, older destination, newer destination, same-created digest conflict, and different source id conflict. It does not decide whether to skip, replace, force, or fail; publish planning maps outcomes to actions.
+
+## Failure Behavior
+
+Parsing rejects invalid JSON, trailing data, missing required fields, invalid timestamps, invalid embedded manifests, duplicate outputs, invalid output paths, unsupported output kinds, missing generated transforms, invalid URLs, invalid digests, and negative sizes.
+
+## Tests To Inspect
+
+- `internal/state/distributor_test.go`
+- `internal/state/compare_test.go`
+- `internal/publish/*_test.go`
+
+## Architectural Invariants
 
 - `.distributor.json` is the destination sentinel and state record.
-- Embedded source manifests use the same validation rules as source bundles.
+- Comparison does not mutate storage.
+- Embedded source manifests use the source bundle contract.
 - Generated outputs always record a transform id.
 - Stored URLs are optional and must be absolute HTTP or HTTPS URLs when present.
-- Comparison returns outcomes and reasons; it does not mutate storage.
 - `distributor_version` is diagnostic metadata, not a comparison key.