fix(ai): align reindex live denominator with the steady-state count

Review fixes for the reindex-progress counter (#242):

1. Denominator jump (478 -> 500 -> 478): reindexWorkspace iterated
   getIdsByWorkspace() (ALL non-deleted pages) but the seed/status use
   countEmbeddablePages (text OR existing-embedding), so the live total exceeded
   the steady-state total whenever empty/text-less pages existed. Add
   PageRepo.getEmbeddablePageIds() that selects the IDs of the EXACT same set
   countEmbeddablePages counts (deletedAt IS NULL AND (text_content matches a
   non-whitespace char OR an EXISTS non-deleted pageEmbeddings row)), and have
   reindexWorkspace iterate THAT set with total = its length. Iteration set and
   count source change together, so done reaches exactly total == the
   steady-state denominator. Dropping text-less pages is correct (reindexPage
   no-ops on them; a page that lost its text but still has stale embeddings is in
   the set via the EXISTS clause and still gets its stale rows cleared). Removed
   the contradictory "worker overwrites with the real page count" / "denominator
   matches" comment.

2. Mid-run re-trigger reset: reindex() unconditionally re-seeded done=0 before an
   enqueue that de-dupes a running job, so a second click/admin/tab reset the
   visible counter while the worker kept incrementing. Now seed only when
   get(workspaceId) === null; the worker's own start() remains the single
   authoritative reset.

3. TTL: documented that it is intentionally tied to write progress
   (start/increment) and never refreshed on get(), so a dead worker's record
   can't be kept alive forever by client polling.

Tests: new embedding-reindex-progress.service.spec.ts (fake ioredis: hash ->
ReindexProgress, malformed/missing/non-numeric -> null, non-finite startedAt ->
0, hgetall throws -> null, start/increment issue hset/hincrby+expire and swallow
Redis errors); reindex() seed order + no-reseed-when-active guard; getMasked
live test now uses progress.total=500 vs DB 478 to pin the progress branch;
indexer specs updated to mock getEmbeddablePageIds.

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

apps/server/src/core/ai-chat/embedding/embedding-indexer.service.spec.ts

@@ -14,7 +14,8 @@ import { AiEmbeddingNotConfiguredException } from '../../../integrations/ai/ai-e
  * reindexWorkspace actually touches:
  *   - aiService.getEmbeddingModel -> a model string so the up-front configured
  *     check passes,
- *   - pageRepo.getIdsByWorkspace -> three page ids,
+ *   - pageRepo.getEmbeddablePageIds -> three page ids (the embeddable set the
+ *     reindex iterates),
  *   - service.reindexPage -> spied per test to drive the per-page outcome.
  *
  * The point under test is the catch block: a FATAL provider error (auth/billing)
@@ -26,7 +27,7 @@ describe('EmbeddingIndexerService.reindexWorkspace fail-fast', () => {
 
   function makeService() {
     const pageRepo = {
-      getIdsByWorkspace: jest.fn().mockResolvedValue(['p1', 'p2', 'p3']),
+      getEmbeddablePageIds: jest.fn().mockResolvedValue(['p1', 'p2', 'p3']),
     };
     const pageEmbeddingRepo = {};
     const aiService = {
@@ -102,7 +103,7 @@ describe('EmbeddingIndexerService.reindexWorkspace progress', () => {
 
   function makeService(pageIds: string[] = ['p1', 'p2', 'p3']) {
     const pageRepo = {
-      getIdsByWorkspace: jest.fn().mockResolvedValue(pageIds),
+      getEmbeddablePageIds: jest.fn().mockResolvedValue(pageIds),
     };
     const pageEmbeddingRepo = {};
     const aiService = {

apps/server/src/core/ai-chat/embedding/embedding-indexer.service.ts

@@ -215,12 +215,19 @@ export class EmbeddingIndexerService {
         throw err;
       }
 
-      const pageIds = await this.pageRepo.getIdsByWorkspace(workspaceId);
+      // Iterate the EMBEDDABLE set (same predicate as countEmbeddablePages), NOT
+      // every non-deleted page: this makes `total` here equal the steady-state
+      // denominator, so the live counter climbs 0 -> total and matches the
+      // before/after DB count exactly (no 478 -> 500 -> 478 denominator jump).
+      // Text-less pages are correctly skipped — reindexPage no-ops on them, and
+      // a page that lost its text but still has stale embeddings IS in this set
+      // (the EXISTS clause) so it is still visited and its stale rows cleared.
+      const pageIds = await this.pageRepo.getEmbeddablePageIds(workspaceId);
       const total = pageIds.length;
       const startedAt = Date.now();
-      // Publish the live run progress (overwrites the enqueue-time placeholder
-      // with the real page count, done back to 0) so the settings status can
-      // report done climbing 0 -> total while this reindex runs.
+      // Publish the live run progress over this same set (done reset to 0). The
+      // counter increments once per iterated page and reaches exactly `total`,
+      // which equals countEmbeddablePages — the steady-state denominator.
       await this.reindexProgress.start(workspaceId, total);
       this.logger.log(
         `reindexWorkspace: starting reindex of ${total} page(s) for workspace ${workspaceId}`,