Remove internal filament management, integrate FilamentDB, add job detail page

Filament removal:
- Deleted app/models/filament.py, routers/filaments.py, templates/filaments.html
- Migration 0009: drops filaments table and filament_id FK from print_jobs
- Removed Filaments from sidebar and all internal references

FilamentDB integration (read-only):
- app/filamentdb.py: GET /reports/stock with 5-min in-memory cache
- available_materials() / available_colors() populate job form dropdowns
- Falls back to static constants if FilamentDB unreachable
- Dashboard filament count now from FilamentDB rolls_in_stock
- FILAMENTDB_URL added to .env.install; httpx added to requirements

Job detail page (/jobs/{id}):
- Two cards: Job info (customer, material, printer, bracket, timing, cost)
  and File & Geometry (bounding box + volume from stl_cache)
- Log timeline with Add Entry modal
- Filename in jobs list links to detail page

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/templates/base.html

@@ -50,8 +50,7 @@
       <li><a href="/printers"  class="nav-link {% if active == 'printers'  %}active{% endif %}"><i class="bi bi-printer me-2"></i>Printers</a></li>
       <li><a href="/jobs"      class="nav-link {% if active == 'jobs'      %}active{% endif %}"><i class="bi bi-list-task me-2"></i>Jobs</a></li>
       <li><a href="/brackets"  class="nav-link {% if active == 'brackets'  %}active{% endif %}"><i class="bi bi-collection me-2"></i>Brackets</a></li>
-      <li><a href="/filaments" class="nav-link {% if active == 'filaments' %}active{% endif %}"><i class="bi bi-record-circle me-2"></i>Filaments</a></li>
-      <li><a href="/todos"     class="nav-link {% if active == 'todos'     %}active{% endif %}"><i class="bi bi-check2-square me-2"></i>To-Do</a></li>
+<li><a href="/todos"     class="nav-link {% if active == 'todos'     %}active{% endif %}"><i class="bi bi-check2-square me-2"></i>To-Do</a></li>
       <li><a href="/pricing"   class="nav-link {% if active == 'pricing'   %}active{% endif %}"><i class="bi bi-currency-euro me-2"></i>Pricing</a></li>
     </ul>
   </nav>