feat: return-to-project redirects from create/edit forms

When creating or editing items from a project detail tab, users now
return to that project's tab instead of the entity's own page.
Edit links pass from_project param; forms include hidden field.
Reassigning to a different project redirects to the new project.
Decisions/meetings create from project context inserts junction rows.
File uploads from project context redirect back to project files tab.

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

routers/contacts.py

@@ -138,7 +138,7 @@ async def contact_detail(contact_id: str, request: Request, db: AsyncSession = D
 
 
 @router.get("/{contact_id}/edit")
-async def edit_form(contact_id: str, request: Request, db: AsyncSession = Depends(get_db)):
+async def edit_form(contact_id: str, request: Request, from_project: Optional[str] = None, db: AsyncSession = Depends(get_db)):
     repo = BaseRepository("contacts", db)
     sidebar = await get_sidebar_data(db)
     item = await repo.get(contact_id)
@@ -159,6 +159,7 @@ async def edit_form(contact_id: str, request: Request, db: AsyncSession = Depend
         "request": request, "sidebar": sidebar,
         "page_title": "Edit Contact", "active_nav": "contacts",
         "item": item, "all_links": all_links, "linked_links": linked_links,
+        "from_project": from_project or "",
     })
 
 
@@ -174,6 +175,7 @@ async def update_contact(
     phone: Optional[str] = Form(None),
     notes: Optional[str] = Form(None),
     tags: Optional[str] = Form(None),
+    from_project: Optional[str] = Form(None),
     db: AsyncSession = Depends(get_db),
 ):
     repo = BaseRepository("contacts", db)
@@ -224,6 +226,8 @@ async def update_contact(
 
     await db.commit()
 
+    if from_project and from_project.strip():
+        return RedirectResponse(url=f"/projects/{from_project}?tab=contacts", status_code=303)
     return RedirectResponse(url=f"/contacts/{contact_id}", status_code=303)