Support flexible configuration formats in filesystem mount parser

[Copilot]

Configuration parser rejected addr=0x80303F1,size=0 (short keys, comma-separated) causing mount failures with "Unknown config key" warnings. Parser only accepted flash_addr=X;flash_size=Y format.

Changes

• Parser accepts short and long key names: addr/flash_addr, size/flash_size
• Parser accepts comma or semicolon separators: , and ;
• Updated documentation with supported format variants

Example

All formats now work:

// Original (still supported)
dmfsi_dmffs_init("flash_addr=0x08080000;flash_size=0x80000");

// User's format (now supported)
dmfsi_dmffs_init("addr=0x80303F1,size=0");

// Mixed variants
dmfsi_dmffs_init("addr=0x08080000;size=0x80000");
dmfsi_dmffs_init("flash_addr=0x08080000,flash_size=0x80000");

Parser implementation in parse_config_string() now checks key length and compares against both variants before accepting/rejecting keys.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Problem z montowaniem systemu plików</issue_title>
<issue_description>jest jakiś problem z montowaniem tego systemu plików, w dmod-boot mam:

[WARN] Flash address not configured. 'FLASH_FS_ADDR' variable is not set (hex value required)
[WARN] Flash size not configured. 'FLASH_FS_SIZE' variable is not set (hex value required)
[INFO] Module enabled: dmffs
[WARN] Unknown config key: '%.*s'
[INFO] File system 'dmffs' mounted at '/configs' successfully
[ERROR] Failed to mount config filesystem at /configs/

Czyli niby się udalo a potem jest fail. W systemie plikow tez nie jest widoczny - no i ten warning jest dziwny. Opcje przekazane do montowania to:
addr=0x80303F1,size=0</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Problem z montowaniem systemu plików #24

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