Refactor Lost/Found modules: eliminate ~900 lines of duplication

[Copilot]

Lost and Found modules in both Python and Go backends contained near-identical implementations differing only in table names.

Changes

Python Backend

• Created generic modules: lost_found_generic.py (queries) and generic_handlers.py (routes)
• Consolidated logic: Reduced route handlers from 162/155 lines → 39 lines each (-76%)
• Parameterized table names: Functions accept table_name parameter instead of hardcoding "lost"/"found"

Go Backend

• Created generic modules: lostandfound_generic.go (db layer) and controller equivalent
• Consolidated logic: Reduced controllers from 344/291 lines → 30/20 lines each (-91%)
• Added schema: LostFoundItem type for shared item representation

Security

• Table name validation: Whitelist enforcement prevents SQL injection via dynamic table names
• Parameterized queries: All user inputs use bound parameters (e.g., %s in Python, $1 in Go)
• CodeQL verified: 0 alerts

Example

Before (lost.py):

@router.post("/add_item")
async def add_item(request, form_data, images):
    user_id = get_user_id(request)
    with conn.cursor() as cur:
        cur.execute(insert_in_lost_table(form_data, user_id))
        # ... 20+ more lines of S3 upload logic

After:

@router.post("/add_item")
async def add_item(request, form_data, images):
    return await add_item_handler(
        request, form_data, images, 
        "lost", insert_in_lost_table, insert_lost_images
    )

All API endpoints remain unchanged.

Original prompt

Find and refactor duplicated code

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