refactor(#1510): relocate getDirName + processAttribution out of bin/install.js (#1512)

Phase 1 of epic #1507 (ADR-1508): behavior-preserving relocation of the pure
rewrite-engine helpers out of the hand-authored installer so the conversion
module can own them without importing bin/install.js.

- getDirName -> src/runtime-name-policy.cts (pure runtime->dir-name switch).
- processAttribution -> src/runtime-artifact-conversion.cts (pure Co-Authored-By
  content transform).
- bin/install.js imports both back via destructure/binding and re-exports
  getDirName unchanged (Hyrum: install.test.cjs + runtime install tests import
  getDirName from bin/install.js).

Two refinements to ADR-1508's Phase 1 (verified against the source):
- getCommitAttribution STAYS in bin/install.js: it is impure install-time
  config I/O (reads runtime settings.json, uses install-time config-dir state +
  attributionCache), not a content transform. Phase 2 will inject the resolved
  attribution into the engine rather than move this function.
- The convertClaudeToAugmentMarkdown dedup is deferred to Phase 2's cleanup: the
  local copy is entangled with a converter cluster (convertSlashCommandsTo
  AugmentSkillMentions is used only by it; the family is partly dead-local via
  the ...runtimeArtifactConversion export spread), deduping only augment would be
  arbitrary, and it is not required to unblock Phase 2 (the engine will call the
  conversion module's own copy when it moves).

New tests/enh-1510-*.test.cjs: getDirName at its new home (all runtimes +
fallback + install.js re-export identity) and processAttribution
(null/undefined/string/$-escape/CRLF/global). 487 affected-suite tests green.


Claude-Session: https://claude.ai/code/session_0187qgypdy1wkWRpdaf2hRuD

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/runtime-artifact-conversion.cts

@@ -2095,7 +2095,36 @@ function convertClaudeCommandToKiloSkill(content, skillName) {
 }
 
 
+/**
+ * Apply Co-Authored-By attribution policy to file content.
+ *   - null      -> remove the Co-Authored-By line and its preceding blank line
+ *   - undefined -> leave content unchanged
+ *   - string    -> replace the value ($ escaped to block backreference injection)
+ *
+ * Pure content transform, relocated from bin/install.js per ADR-1508
+ * (epic #1507, #1510 Phase 1). NOTE: getCommitAttribution stays in the
+ * installer — it is impure install-time config I/O (reads runtime
+ * settings.json, uses the install-time config-dir + cache), not a content
+ * transform, so it does not belong behind this content-conversion seam.
+ */
+function processAttribution(
+  content: string,
+  attribution: string | null | undefined,
+): string {
+  if (attribution === null) {
+    // Remove Co-Authored-By lines and the preceding blank line
+    return content.replace(/(\r?\n){2}Co-Authored-By:.*$/gim, '');
+  }
+  if (attribution === undefined) {
+    return content;
+  }
+  // Replace with custom attribution (escape $ to prevent backreference injection)
+  const safeAttribution = attribution.replace(/\$/g, '$$$$');
+  return content.replace(/Co-Authored-By:.*$/gim, `Co-Authored-By: ${safeAttribution}`);
+}
+
 export = {
+  processAttribution,
   yamlIdentifier,
   yamlQuote,
   toSingleLine,

src/runtime-name-policy.cts

@@ -88,3 +88,32 @@ export function resolveRuntimeNameFromCandidates(...candidates: unknown[]): stri
   }
   return null;
 }
+
+/**
+ * Map a canonical runtime id to its on-disk local config directory name
+ * (e.g. `cursor` -> `.cursor`, `windsurf` -> `.devin`). Unknown/empty inputs
+ * fall back to `.claude`.
+ *
+ * Pure runtime-identity projection. Relocated from `bin/install.js` per
+ * ADR-1508 (epic #1507, #1510 Phase 1) so the Runtime Artifact Conversion
+ * Module's rewrite engine can consume it without importing the installer.
+ * `bin/install.js` re-exports this same function for back-compat.
+ */
+export function getDirName(runtime: string): string {
+  if (runtime === 'copilot') return '.github';
+  if (runtime === 'opencode') return '.opencode';
+  if (runtime === 'gemini') return '.gemini';
+  if (runtime === 'kilo') return '.kilo';
+  if (runtime === 'codex') return '.codex';
+  if (runtime === 'antigravity') return '.agents';
+  if (runtime === 'cursor') return '.cursor';
+  if (runtime === 'windsurf') return '.devin';
+  if (runtime === 'augment') return '.augment';
+  if (runtime === 'trae') return '.trae';
+  if (runtime === 'qwen') return '.qwen';
+  if (runtime === 'hermes') return '.hermes';
+  if (runtime === 'kimi') return '.kimi-code';
+  if (runtime === 'codebuddy') return '.codebuddy';
+  if (runtime === 'cline') return '.cline';
+  return '.claude';
+}