Add MSTP implementation and update network/frontend files

[RamProsad2]

MSTP on VLANs Demo - Bridge: br0, VLANs: 10 & 20, MSTI: 1

1.MSTP Bridge Status
sudo mstpctl showbridge br0

Output:
br0 CIST info
enabled yes
bridge id 8.000.0A:17:5F:11:1D:17
force protocol version rstp
topology change port veth1

2. MSTI Tree (VLAN group)
   sudo mstpctl showtree br0 1

Output:
br0 MSTI 1 info
bridge id 8.001.0A:17:5F:11:1D:17
regional root 8.001.0A:17:5F:11:1D:17
root port none
topology change port veth1

3. VLAN → FID mapping
   sudo mstpctl showvid2fid br0
   Output:
   FID 1: 10,20 # VLANs 10 & 20 are grouped in FID 1

4. FID → MSTI mapping
   sudo mstpctl showfid2mstid br0

Output:
MSTID 1: 1 # FID 1 belongs to MSTI 1

5. Port roles (per MSTI)
   sudo mstpctl showport br0 veth1
   sudo mstpctl showport br0 veth2

Output:
veth1 8.001 forw ... Desg # Forwarding (Designated) for VLANs 10 & 20
veth2 8.002 disc ... Back # Blocking (Backup) for VLANs 10 & 20

6. Optional: Simulate topology change
   sudo ip link set veth2 down
   sudo ip link set veth2 up
   sudo mstpctl showtree br0 1
   sudo mstpctl showport br0 veth1
   sudo mstpctl showport br0 veth2

MSTP detects topology changes and updates port roles automatically

Conclusion

• MSTP is running on bridge br0
• VLANs 10 & 20 are in MSTI 1 and VLAN-aware
• Port roles assigned correctly (forwarding/blocking)
• MSTP reacts to topology changes ensuring loop-free forwarding