feat: unify execution and add workspace file imports

Remove Ask/Execute modes and general product tool approvals so requests use the selected runtime, enabled capabilities, and execution account permissions. Migrate retired application metadata while preserving user content.

Retire the Results page while retaining conversation images and stored artifacts. Add local and remote workspace file imports, timestamps and sorting, improve image discovery and saving, and refine workspace navigation and supervision responsiveness. Include the accompanying web-search changes, tests, probes, and product documentation.

Remote imports require an updated Agent. Existing artifacts are not automatically copied into project directories. Validation evidence and outstanding failures remain documented in feature progress files; no full test suite or real-model calls were rerun for this commit.

Release note: Run requests without switching work modes, import files into a selected local or remote workspace folder, sort workspace files by date, and keep using conversation images after removal of the Results page.

src/main/assistant/heartbeat-database.test.ts

@@ -9,6 +9,11 @@ import {
 } from './assistant-database'
 
 const temporaryDirectories: string[] = []
+const historicalModeColumns = `
+  ALTER TABLE projects ADD COLUMN default_work_mode TEXT NOT NULL DEFAULT 'ask';
+  ALTER TABLE conversations ADD COLUMN work_mode TEXT NOT NULL DEFAULT 'ask';
+  ALTER TABLE tasks ADD COLUMN work_mode TEXT NOT NULL DEFAULT 'execute';
+`
 
 afterEach(async () => {
   await Promise.all(
@@ -69,7 +74,6 @@ describe('AssistantDatabase heartbeat persistence', () => {
     const schedule = database.createSchedule({
       title: 'Existing schedule',
       prompt: 'Keep this schedule',
-      workMode: 'ask',
       recurrence: 'weekly',
       nextRunAt: '2026-08-03T09:00:00.000Z'
     })
@@ -87,7 +91,7 @@ describe('AssistantDatabase heartbeat persistence', () => {
       DROP TABLE IF EXISTS supervision_review_sources; DROP TABLE IF EXISTS supervision_review_runs;
       DROP TABLE review_checkpoints; ALTER TABLE messages DROP COLUMN review_revision;
       ALTER TABLE magic_note_entries DROP COLUMN source_json;
-      PRAGMA user_version = 2`)
+      ${historicalModeColumns} PRAGMA user_version = 2`)
     raw.close()
 
     const migrated = new AssistantDatabase(path)
@@ -150,7 +154,7 @@ describe('AssistantDatabase heartbeat persistence', () => {
       DROP TABLE IF EXISTS supervision_review_sources; DROP TABLE IF EXISTS supervision_review_runs;
       DROP TABLE review_checkpoints; ALTER TABLE messages DROP COLUMN review_revision;
       ALTER TABLE magic_note_entries DROP COLUMN source_json;
-      PRAGMA user_version = 20`)
+      ${historicalModeColumns} PRAGMA user_version = 20`)
     raw.close()
 
     const migrated = new AssistantDatabase(path)
@@ -169,13 +173,11 @@ describe('AssistantDatabase heartbeat persistence', () => {
       name: 'Second',
       description: '',
       rootPath: 'C:\\Second',
-      defaultWorkMode: 'ask'
     })
     const excluded = database.createProject({
       name: 'Excluded',
       description: '',
       rootPath: 'C:\\Excluded',
-      defaultWorkMode: 'ask'
     })
     database.replaceConversations(
       [first, second, excluded].map((project, index) => ({
@@ -192,7 +194,6 @@ describe('AssistantDatabase heartbeat persistence', () => {
         projectId: project.id,
         title: project.name,
         instructions: '',
-        workMode: 'ask'
       })
       database.createMemory({
         scope: 'project',