feat: isolate Claude and Codex session sources

Persist platform_source across session creation, transcript ingestion, API query paths, and viewer state so Claude and Codex data can coexist without bleeding into each other.

- add platform-source normalization helpers and persist platform_source in sdk_sessions via migration 24 with backfill and indexing
- thread platformSource through CLI hooks, transcript processing, context generation, pagination, search routes, SSE payloads, and session management
- expose source-aware project catalogs, viewer tabs, context preview selectors, and source badges for observations, prompts, and summaries
- start the transcript watcher from the worker for transcript-based clients and preserve platform source during Codex ingestion
- auto-start the worker from the MCP server for MCP-only clients and tighten stdio-driven cleanup during shutdown
- keep createSDKSession backward compatible with existing custom-title callers while allowing explicit platform source forwarding

src/services/sqlite/SessionSearch.ts

@@ -3,6 +3,7 @@ import { TableNameRow } from '../../types/database.js';
 import { DATA_DIR, DB_PATH, ensureDir } from '../../shared/paths.js';
 import { logger } from '../../utils/logger.js';
 import { isDirectChild } from '../../shared/path-utils.js';
+import { AppError } from '../server/ErrorHandler.js';
 import {
   ObservationSearchResult,
   SessionSummarySearchResult,
@@ -22,6 +23,8 @@ import {
 export class SessionSearch {
   private db: Database;
 
+  private static readonly MISSING_SEARCH_INPUT_MESSAGE = 'Either query or filters required for search';
+
   constructor(dbPath?: string) {
     if (!dbPath) {
       ensureDir(DATA_DIR);
@@ -280,7 +283,7 @@ export class SessionSearch {
     if (!query) {
       const filterClause = this.buildFilterClause(filters, params, 'o');
       if (!filterClause) {
-        throw new Error('Either query or filters required for search');
+        throw new AppError(SessionSearch.MISSING_SEARCH_INPUT_MESSAGE, 400, 'INVALID_SEARCH_REQUEST');
       }
 
       const orderClause = this.buildOrderClause(orderBy, false);
@@ -317,7 +320,7 @@ export class SessionSearch {
       delete filterOptions.type;
       const filterClause = this.buildFilterClause(filterOptions, params, 's');
       if (!filterClause) {
-        throw new Error('Either query or filters required for search');
+        throw new AppError(SessionSearch.MISSING_SEARCH_INPUT_MESSAGE, 400, 'INVALID_SEARCH_REQUEST');
       }
 
       const orderClause = orderBy === 'date_asc'
@@ -551,7 +554,7 @@ export class SessionSearch {
     // FILTER-ONLY PATH: When no query text, query user_prompts table directly
     if (!query) {
       if (baseConditions.length === 0) {
-        throw new Error('Either query or filters required for search');
+        throw new AppError(SessionSearch.MISSING_SEARCH_INPUT_MESSAGE, 400, 'INVALID_SEARCH_REQUEST');
       }
 
       const whereClause = `WHERE ${baseConditions.join(' AND ')}`;