Add agent working directory setting to run coding agents from repo directory (Vibe Kanban) (#1617)

* Done! The migration has been updated to copy `dev_script_working_dir` values to `agent_working_dir` for existing projects. The change:

**`vibe-kanban/crates/db/migrations/20251219000000_add_agent_working_dir_to_projects.sql`**:
```sql
-- Add column with empty default first
ALTER TABLE projects ADD COLUMN agent_working_dir TEXT DEFAULT '';

-- Copy existing dev_script_working_dir values to agent_working_dir
UPDATE projects SET agent_working_dir = dev_script_working_dir WHERE dev_script_working_dir IS NOT NULL AND dev_script_working_dir != '';
```

This ensures that when the migration runs, existing projects will have their `agent_working_dir` automatically populated from their existing `dev_script_working_dir` setting.

* Done! The migration has been updated to only copy `dev_script_working_dir` to `agent_working_dir` for single-repo projects. Multi-repo projects will keep `agent_working_dir` empty (None).

The key change in the migration:
```sql
UPDATE projects SET agent_working_dir = dev_script_working_dir
WHERE dev_script_working_dir IS NOT NULL
  AND dev_script_working_dir != ''
  AND (SELECT COUNT(*) FROM project_repos WHERE project_repos.project_id = projects.id) = 1;
```

The subquery `(SELECT COUNT(*) FROM project_repos WHERE project_repos.project_id = projects.id) = 1` ensures only projects with exactly one repository get the default value copied.

* Done! All tasks completed:

1. **Resolved the rebase conflict** in `task_attempts.rs` - removed the duplicate `follow_up` function since it was moved to `sessions/mod.rs` on main

2. **Updated `sessions/mod.rs`** with the `working_dir` changes - added the code to get `agent_working_dir` from project settings and pass it to both `CodingAgentFollowUpRequest` and `CodingAgentInitialRequest`

3. **Ran `npm run prepare-db`** - successfully prepared the database and updated sqlx cache

4. **Verified compilation** - all crates compile successfully

The migration now only copies `dev_script_working_dir` to `agent_working_dir` for single-repo projects (projects with exactly 1 repo in `project_repos` table). Multi-repo projects will keep `agent_working_dir` empty.

* Done. Removed all 6 comments as requested.

* Done! The implementation is now complete:

1. **Database migration** - Copies `dev_script_working_dir` to `agent_working_dir` for single-repo projects at migration time
2. **Runtime backfill** - `backfill_repo_names()` in `container.rs` sets `agent_working_dir` for existing single-repo projects where it's still empty
3. **Project creation** - New single-repo projects automatically get `agent_working_dir` set to the repo name

All three scenarios are now covered for setting `agent_working_dir` on single-repo projects.

* Done! The frontend UI for `agent_working_dir` has been added:

1. Added `agent_working_dir: string` to `ProjectFormState` interface
2. Added `agent_working_dir` to `projectToFormState` function
3. Added `agent_working_dir` to the `handleSave` payload
4. Added the input field after the dev server working directory input

* All tasks are complete. The implementation is finished:

**Summary of changes:**

1. **Project model**: Renamed `agent_working_dir` to `default_agent_working_dir` - this is now a default value for new workspaces

2. **Workspace model**: Added `agent_working_dir` field - this captures the project's default at workspace creation time

3. **Workspace creation**: Updated `create_task_attempt` to fetch the project's `default_agent_working_dir` and pass it to the workspace

4. **Execution sites**: Updated all 4 locations to use `workspace.agent_working_dir` instead of `project.default_agent_working_dir`:
   - `container.rs` (start_workspace)
   - `container.rs` (start_queued_follow_up)
   - `sessions/mod.rs` (follow_up)
   - `task_attempts/pr.rs` (trigger_pr_description_follow_up)

5. **Frontend**: Updated `ProjectSettings.tsx` to use `default_agent_working_dir`

6. **Migrations**: Two migrations added - one to rename the project column and one to add the workspace column

* Cleanup script changes for workspace a87cad74-ed7c-402b-b3f3-413a939a13a9

* Done. The migrations have been squashed into a single migration file `20251219000000_add_agent_working_dir_to_projects.sql` which now handles both the project and workspace table changes. The separate workspace migration file has been deleted and `npm run prepare-db` completes successfully.

* Done. The i18n check passes with all checks passing:
- No new literal strings introduced
- No duplicate keys found in JSON files
- Translation keys are consistent across locales (en, es, ja, ko, zh-Hans)

* All checks pass:
- `npm run check` ✅ (frontend TypeScript and backend Rust)
- `npm run prepare-db` ✅ (migrations and sqlx query cache)

* `npm run lint` passes now.

* Done. I've added the logic to `crates/services/src/services/project.rs` in the `add_repository()` function. When a second repository is added to a project (repo count becomes exactly 2), the `default_agent_working_dir` field is automatically cleared by setting it to an empty string.

* Cleanup script changes for workspace a87cad74-ed7c-402b-b3f3-413a939a13a9

* Both checks pass. The fix now correctly:
1. Counts repos **before** adding the new one
2. Only clears `default_agent_working_dir` if the previous count was exactly 1 (meaning we're going from 1 to 2 repos)

* Done. The fix now:

1. Added a dedicated `Project::clear_default_agent_working_dir()` method in `crates/db/src/models/project.rs` that only updates the `default_agent_working_dir` field without touching other fields
2. Updated `add_repository()` in `crates/services/src/services/project.rs` to use this new method when the repo count goes from 1 to 2

shared/types.ts

@@ -12,11 +12,11 @@ export type SharedTask = { id: string, organization_id: string, project_id: stri
 
 export type UserData = { user_id: string, first_name: string | null, last_name: string | null, username: string | null, };
 
-export type Project = { id: string, name: string, dev_script: string | null, dev_script_working_dir: string | null, remote_project_id: string | null, created_at: Date, updated_at: Date, };
+export type Project = { id: string, name: string, dev_script: string | null, dev_script_working_dir: string | null, default_agent_working_dir: string | null, remote_project_id: string | null, created_at: Date, updated_at: Date, };
 
 export type CreateProject = { name: string, repositories: Array<CreateProjectRepo>, };
 
-export type UpdateProject = { name: string | null, dev_script: string | null, dev_script_working_dir: string | null, };
+export type UpdateProject = { name: string | null, dev_script: string | null, dev_script_working_dir: string | null, default_agent_working_dir: string | null, };
 
 export type SearchResult = { path: string, is_file: boolean, match_type: SearchMatchType, };
 
@@ -70,7 +70,7 @@ export type Image = { id: string, file_path: string, original_name: string, mime
 
 export type CreateImage = { file_path: string, original_name: string, mime_type: string | null, size_bytes: bigint, hash: string, };
 
-export type Workspace = { id: string, task_id: string, container_ref: string | null, branch: string, setup_completed_at: string | null, created_at: string, updated_at: string, };
+export type Workspace = { id: string, task_id: string, container_ref: string | null, branch: string, agent_working_dir: string | null, setup_completed_at: string | null, created_at: string, updated_at: string, };
 
 export type Session = { id: string, workspace_id: string, executor: string | null, created_at: string, updated_at: string, };
 
@@ -437,13 +437,23 @@ export type CodingAgentInitialRequest = { prompt: string,
 /**
  * Executor profile specification
  */
-executor_profile_id: ExecutorProfileId, };
+executor_profile_id: ExecutorProfileId, 
+/**
+ * Optional relative path to execute the agent in (relative to container_ref).
+ * If None, uses the container_ref directory directly.
+ */
+working_dir: string | null, };
 
 export type CodingAgentFollowUpRequest = { prompt: string, session_id: string, 
 /**
  * Executor profile specification
  */
-executor_profile_id: ExecutorProfileId, };
+executor_profile_id: ExecutorProfileId, 
+/**
+ * Optional relative path to execute the agent in (relative to container_ref).
+ * If None, uses the container_ref directory directly.
+ */
+working_dir: string | null, };
 
 export type CommandExitStatus = { "type": "exit_code", code: number, } | { "type": "success", success: boolean, };