refactor(indexer): route claude indexing through adapter + persist (Phase 5b-2b)

buildIndex's claude branch now parses via providers/claude.ts and writes via
persist.ts instead of the inlined indexJsonl. Behavior is equivalent — the full
buildIndex integration suite (runtime.test.mjs) stays green, 116/116 — and a
force rebuild of the real ~/.obelisk index (327 sessions, 119k messages)
reproduced identical session counts with project_path fully populated.

codex, indexSubagentMeta, workflows, history and the project_path pass are
untouched. indexJsonl is now unused by buildIndex (kept for its drift test;
removed once codex is migrated).

Adds tests/incremental-index.test.mjs: verifies resume/accumulate through the
full buildIndex path (append new lines to an indexed session → incremental
build resumes from the cursor, message_count accumulates, no duplicates). The
30s shouldSkipBuild debounce is cleared in-test so the incremental run fires.

scripts/indexer.mjs

@@ -1,4 +1,6 @@
 import { CLAUDE_DIR, CODEX_DIR, openDb, rebuildMemoryFts, trunc, truncJson, extractText, extractContentType, extractMessageIsMeta, filePath, isDir, readLines, fs, path } from './db.mjs';
+import { persist } from './persist.ts';
+import { parse as claudeParse } from './providers/claude.ts';
 
 const PROJECTS_DIR = path.join(CLAUDE_DIR, 'projects');
 const HISTORY_PATH = path.join(CLAUDE_DIR, 'history.jsonl');
@@ -782,7 +784,14 @@ function buildIndex({ force = false } = {}) {
       if (f.source === 'codex') {
         indexCodexJsonl(db, f);
       } else {
-        indexJsonl(db, f);
+        // Claude transcripts now go through the pure adapter + shared persist
+        // (docs/adr/0001). needsReindex keeps the "skip unchanged file" fast path;
+        // the cursor's line count drives incremental resume inside parse().
+        const { needed, skip } = needsReindex(db, f.path);
+        if (needed) {
+          const unit = { key: f.path, sessionId: f.sessionId, project: f.project, isSubagent: f.isSubagent, agentId: f.agentId };
+          persist(db, unit, claudeParse(unit, skip > 0 ? `0:${skip}` : null));
+        }
         indexSubagentMeta(db, f);
       }
       db.exec('COMMIT');