feat(#137): add doc-map input for path-scoped doc injection

- New --doc-map flag (DOC_MAP_FILE env var): path to YAML config mapping
  source path globs to governing design docs
- New --doc-map-max-bytes flag (DOC_MAP_MAX_BYTES env var): cap on total
  injected doc content, default 100KB
- review/docmap.go: DocMapConfig parsing, glob matching with ** support,
  doc loading via VCS with directory expansion and size guard
- budget.Sections: new DesignDocs field, trimmed after conventions
- budget.buildResult: injects DesignDocs under ## Design Documents heading
- action.yml: doc-map and doc-map-max-bytes inputs wired to env vars
- CHANGELOG.md: created with unreleased entry
- Tests: ParseDocMapConfig, MatchDocs, globMatch, LoadMatchingDocs

.gitea/actions/review/action.yml

@@ -130,6 +130,17 @@ inputs:
     description: 'Path to custom persona JSON file'
     required: false
     default: ''
+  doc-map:
+    description: >-
+      Path to a YAML file mapping source path globs to governing design docs.
+      review-bot intersects the map with changed PR paths and injects matching
+      docs as context alongside the diff.
+    required: false
+    default: ''
+  doc-map-max-bytes:
+    description: 'Maximum bytes of injected doc content from doc-map (default 102400 = 100KB)'
+    required: false
+    default: '102400'
 
 runs:
   using: 'composite'
@@ -493,6 +504,8 @@ runs:
         SYSTEM_PROMPT_FILE: ${{ inputs.system-prompt-file }}
         PERSONA: ${{ inputs.persona }}
         PERSONA_FILE: ${{ inputs.persona-file }}
+        DOC_MAP_FILE: ${{ inputs.doc-map }}
+        DOC_MAP_MAX_BYTES: ${{ inputs.doc-map-max-bytes }}
         AICORE_CLIENT_ID: ${{ inputs.aicore-client-id }}
         AICORE_CLIENT_SECRET: ${{ inputs.aicore-client-secret }}
         AICORE_AUTH_URL: ${{ inputs.aicore-auth-url }}