fix: FastFlightsAdapter fails silently on domestic Indian routes (INR currency + string stops)

[KrishnaRaheja]

Describe the bug

For domestic Indian flight searches (e.g. BOM→DEL, DEL→BOM), the FastFlightsAdapter returns 0 results despite receiving raw flight data from the API (e.g. 533 raw responses → 0 parsed). All flights are silently dropped inside the per-flight error recovery loop.

Root cause (two bugs in _process_flights):

1. String stops field — The fast_flights library returns flight.stops as a string ("Nonstop", "1 stop") for domestic Indian routes instead of an integer. The comparison flight.stops > max_stops raises TypeError: '>' not supported between instances of 'str' and 'int', causing every flight to be caught and skipped.

2. INR price parsing — _parse_price only strips $ and ,. Indian rupee prices formatted as "₹5,000" fail float() conversion with ValueError, returning 0.0 for all domestic flights (silent data loss — prices recorded as $0).

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To Reproduce

Search for any domestic Indian route, e.g.:

• BOM → DEL, 2026-05-01, economy, max_stops=0
• DEL → BOM, 2026-05-04, economy, max_stops=0

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Expected behavior

Flights are parsed and returned with either the correct INR-converted price or a raw INR amount stored with currency metadata.

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Actual behavior

Found 0 unique flights (533 total raw responses) — all flights silently dropped.

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Affected code

• fast_flights_adapter.py:236 — flight.stops > max_stops (no int coercion)
• fast_flights_adapter.py:317-318 — _parse_price only handles $