Normalize internal component documentation

docs/internal/link.md

@@ -1,27 +1,46 @@
 # Link URL Policy
 
+Audience: developers and LLM coding agents changing `internal/link`.
+
 ## Purpose
 
-`internal/link` defines shared validation for configured and persisted HTTP link URLs.
+`internal/link` owns shared validation for configured and persisted HTTP link URLs.
 
-## Inputs and outputs
+## Inputs And Outputs
 
 Input is a URL string. Output is either nil for an accepted URL or a concise validation error that callers wrap with field context.
 
-## Validation behavior
-
-Accepted URLs must parse successfully, use `http` or `https`, include a host, and omit query strings and fragments.
-
 ## Boundaries
 
-This package validates URL shape only. It does not construct destination output URLs, choose primary URLs, infer public URLs from backend configuration, or read configuration files.
+The package validates URL shape only. It does not construct output URLs, choose primary URLs, infer public URLs from backend configuration, parse config files, or write destination state.
 
-## Tests
+## Config Fields Used
 
-Before changing link URL policy, inspect tests under `internal/link` and callers in `internal/config`, `internal/state`, and `internal/publish`.
+The package does not read config directly. `internal/config` uses it to validate `links.base_url`; `internal/state` uses it to validate persisted `links.primary_url` and output `url` fields.
 
-## Invariants
+## Adapters Used
 
-- Configured `links.base_url`, persisted `links.primary_url`, persisted output `url`, and publish link planning use the same URL policy.
+None.
+
+## State And Manifest Behavior
+
+Destination state URL fields and configured link URLs share the same URL validation policy. Source manifests are not involved.
+
+## Skip And Resume Behavior
+
+None.
+
+## Failure Behavior
+
+Validation rejects parse failures, non-HTTP(S) schemes, missing hosts, query strings, and fragments.
+
+## Tests To Inspect
+
+- `internal/link/url_test.go`
+- callers in `internal/config`, `internal/state`, and `internal/publish`
+
+## Architectural Invariants
+
+- Configured and persisted link URLs use one validation policy.
+- URL construction remains outside `internal/link`.
 - Callers own field-specific error context.
-- URL path construction remains in `internal/publish`.