**Implementation Plan: Expose Level Progress in Profile API**

**Objective**  
Add derived fields `xp_progress_pct` (integer percentage toward next level) and `xp_next_level` (total XP required for next level) to `GET /profile` and `GET /profile/{username}` responses.

**1. Schema Change**  
*File*: `devplacepy/schemas/profile.py`  
- In class `ProfileOut` (line 29–82), add two optional integer fields:  
  `xp_progress_pct: Optional[int] = None`  
  `xp_next_level: Optional[int] = None`  

These fields are optional to avoid breaking existing consumers and because the value is computed at request time.

**2. Route Handler Computation**  
*File*: `devplacepy/routers/profile/index.py`  
`profile_page()` function (starting line 128). Locate the `respond()` call at line 383–445. Before that call, compute:

```python
LEVEL_XP = 100  # constant from devplacepy/utils/rewards.py
xp = user.xp or 0
xp_progress_pct = xp % LEVEL_XP
xp_next_level = ((xp // LEVEL_XP) + 1) * LEVEL_XP
```

Include these values in the context dict passed to `respond()`. For example:

```python
context["xp_progress_pct"] = xp_progress_pct
context["xp_next_level"] = xp_next_level
```

If `user.xp` is `None`, default to `0` for the computation.

**3. Test Addition**  
*File*: `tests/api/profile/index.py` (add a new test function, e.g., `test_profile_contains_xp_progress`)  
- Create a test user with known XP (e.g., 250).  
- Perform `GET /profile` and `GET /profile/{username}`.  
- Assert that the JSON response contains `xp_progress_pct` and `xp_next_level`.  
- Assert that the values match the formula:  
  - `xp_progress_pct` = 250 % 100 = 50  
  - `xp_next_level` = ((250 // 100) + 1) * 100 = 300  

Use the existing test infrastructure (e.g., `test_client` fixture and `auth_headers`).

**4. Verification**  
- Run the profile-specific test file:  
  ```bash
  pip install -e '.[dev]' -q && python -m pytest tests/api/profile/index.py -v
  ```
- Confirm all tests pass (0 failures, 0 errors).  
- Optional: run a broader subset (e.g., `tests/api/`) to ensure no regressions, but the primary verification is the command above.

**Definition of Done**  
- [ ] `ProfileOut` schema includes `xp_progress_pct` and `xp_next_level` fields.  
- [ ] `/profile` and `/profile/{username}` responses contain `xp_progress_pct` (0–99 integer) and `xp_next_level` (total XP for next level).  
- [ ] The new test `test_profile_contains_xp_progress` (or equivalent) exists and verifies the fields for at least one known XP value.  
- [ ] The command `pip install -e '.[dev]' -q && python -m pytest tests/api/profile/index.py` exits with code 0 and shows all tests passing. (Pre-existing Playwright-related failures in other test directories are unrelated and ignored for this change’s validation.)