Fix cost calculation failures: Azure Graph query syntax and data parsing issues

[Copilot]

This PR fixes critical cost calculation failures introduced in PR #183 that were causing Azure Graph query parser errors and invalid data line format issues.

Issues Fixed

1. Azure Pricing API URL Syntax Error

The API URL was missing a closing quote, causing KQL parser failures:

# Before (missing closing quote)
api_url = "https://prices.azure.com/api/retail/prices?currencyCode='GBP&api-version=2021-10-01-preview"

# After (properly quoted)
api_url = "https://prices.azure.com/api/retail/prices?currencyCode='GBP'&api-version=2021-10-01-preview"

2. Azure Graph Query Field Selection Syntax

Invalid KQL syntax using ['tags'] and ['id'] was causing parser failures:

# Before (caused parser failures)
| project name, resourceGroup, subscriptionId, ['tags'], properties.sku.tier, ['id']

# After (valid KQL syntax)
| project name, resourceGroup, subscriptionId, tags, properties.sku.tier, id

3. Resource Data Format Issues

Legacy code was adding leading commas to OS type fields, creating malformed CSV data with extra empty fields:

# Before (caused lines like "VM,Standard_D8ds_v5,,Linux,47")
osType=",$nodepool_os"

# After (clean format produces "VM,Standard_D8ds_v5,Linux,47")
osType="$nodepool_os"

4. Enhanced Error Handling

Added graceful handling for existing malformed data lines:

elif len(currentLine) == 5 and currentLine[2] == "":
    # Handle malformed line: ResourceType,SKU,,OS/Tier,Count
    resource_type = str(currentLine[0])
    sku = str(currentLine[1])
    os_or_tier = str(currentLine[3])  # Skip the empty element
    count = int(currentLine[4])

Error Examples Fixed

Before: Cost calculation failed with errors like:

ERROR: {
    "code": "BadRequest",
    "details": [
        {
            "code": "ParserFailure",
            "message": "ParserFailure",
            "additionalProperties": {"expectedToken": "'"}
        }
    ]
}

Invalid line format: VM,Standard_D8ds_v5,,Linux,47
Invalid line format: VM,Standard_D4ds_v5,,Linux,12

After: All data processes successfully with proper cost calculations.

Testing

• ✅ Python and Bash syntax validation
• ✅ API URL syntax verification
• ✅ Azure Graph query syntax validation
• ✅ End-to-end cost calculation with mixed data formats
• ✅ Backward compatibility with legacy 3-field format
• ✅ Proper handling of malformed lines

Impact

• Resolves Azure Graph query parser failures
• Fixes invalid line format errors in cost calculation
• Maintains full backward compatibility
• Enables accurate cost estimates for all resource types

Fixes #185.

[thomast1906]

@copilot I dont want to use any example data if API is not available, only API data

[Copilot]

@copilot I dont want to use any example data if API is not available, only API data

Removed the fallback pricing mechanism completely. The cost calculator now only uses Azure Pricing API data - when the API is unavailable, it returns 0 and sets ERROR_IN_COSTS flag instead of using example data. Commit e1b87de