Convert values to strings before using join function for jq 1.5 support

[e28eta]

What does this PR aim to accomplish?:

Fixes display empty of data from PADD.sh when running on a machine with jq 1.5.

For a while now my RPi 3 hasn't been showing statistics, and I finally dug into it today. By redirecting stdout to a text file, I was able to see some errors being thrown by the script:

$ ./padd.sh --runonce > padd_output.txt

./padd.sh: 414: [: Illegal number: 
./padd.sh: 419: [: Illegal number: 
./padd.sh: 571: [: Illegal number: 
./padd.sh: 574: [: Illegal number: 
./padd.sh: 585: [: Illegal number: 
./padd.sh: 591: [: Illegal number: 
./padd.sh: 655: [: Illegal number: 
./padd.sh: 1454: ./padd.sh: arithmetic expression: expecting primary: "/60/60/24"

The contents of padd_output.txt were (colorized and centered, and this output is from a different run than the json included below):

 __      __  __   
|__) /\ |  \|  \     Docker , PADD v4.1.0
|   /--\|__/|__/     [✓] DNS   [✓] FTL   

STATS ==========================================================================
 Blocking: 0 domains           Piholed:  [■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■] 0.0% 
 Clients:                                 0 out of 0 queries          
 Latest:   _dns.resolver.arpa                     
 Top Ad:                                          
 Top Dmn:                                         
 Top Clnt:                                        
FTL ============================================================================
 PID:                CPU Use:  0.0%      Mem. Use: 0.0%     
 DNSCache:  insertions,  deletions,  total entries                              
NETWORK ========================================================================
 Hostname:                    
 Interfce:                 TX: 0.0       RX: 0.0      
 IPv4: +                   IPv6:     +                            
DNS ==========================DHCP==============================================
 Servers:   servers            DHCP: Disabled           
 DNSSEC:   Disabled            IPv6 Spt: N/A      
 CdFwding: Disabled            Range N/A                                 
SYSTEM =========================================================================
 Device:   Container                              
 Uptime:                                           Memory:   [··········] 0.0%  
 CPU Temp: N/A       CPU Load: 0.00, 0.00, 0.00    CPU Load: [··········] 0.0%  

Session successfully deleted.

Further investigation (running script with -x and poking around) showed the root cause was that GetPADDData wasn't able to parse the json correctly:

$ response='{"recent_blocked":"mask-h2.icloud.com","active_clients":29,"gravity_size":96372,"top_domain":"api.ring.com","top_blocked":"mask.icloud.com","top_client":"hass.djackson.org","blocking":"enabled","queries":{"total":64273,"blocked":9554,"percent_blocked":14.864717483520508},"cache":{"size":10000,"inserted":3658,"evicted":0},"system":{"uptime":2342,"memory":{"ram":{"total":945360,"free":176408,"used":177216,"available":697372,"%used":18.745874587458747},"swap":{"total":102396,"free":102396,"used":0,"%used":0}},"procs":152,"cpu":{"nprocs":4,"%cpu":3.875,"load":{"raw":[0.109375,0.1240234375,0.1474609375],"percent":[2.734375,3.1005859375,3.6865234375]}},"ftl":{"%mem":13.131505012512207,"%cpu":0.600000023841858}},"node_name":"pihole","host_model":"Raspberry Pi 3 Model B Plus Rev 1.3","iface":{"v4":{"addr":"10.10.10.2","rx_bytes":{"value":53.815188,"unit":"M"},"tx_bytes":{"value":8.070791,"unit":"M"},"num_addrs":1,"name":"eth0","gw_addr":"10.10.10.1"},"v6":{"addr":"fe80::6efa:d688:3be7:840a","num_addrs":1,"name":"eth0","gw_addr":null}},"version":{"core":{"local":{"branch":"master","version":"v6.3","hash":"5a23c9c3"},"remote":{"version":"v6.3","hash":"5a23c9c3"}},"web":{"local":{"branch":"master","version":"v6.4","hash":"cd0c392d"},"remote":{"version":"v6.4","hash":"cd0c392d"}},"ftl":{"local":{"hash":"8d1add8d","branch":"master","version":"v6.4.1","date":"2025-11-27 18:02:19 +0000"},"remote":{"version":"v6.4.1","hash":"8d1add8d"}},"docker":{"local":null,"remote":null}},"config":{"dhcp_active":true,"dhcp_start":"10.10.11.1","dhcp_end":"10.10.11.254","dhcp_ipv6":false,"dns_domain":"djackson.org","dns_port":53,"dns_num_upstreams":2,"dns_dnssec":false,"dns_revServer_active":true,"privacy_level":0},"%mem":13.133621215820312,"%cpu":0.600000023841858,"pid":21126,"sensors":{"cpu_temp":65.528,"hot_limit":60,"unit":"C"},"took":0.011656045913696289}'
$ echo "${response}" | jq -r 'paths(scalars | true) as $p | [$p | join(".")] + [if getpath($p)!=null then getpath($p) else "null" end] | join("=")'
recent_blocked=mask-h2.icloud.com
jq: error (at <stdin>:1): string ("=") and number (29) cannot be added

Unlike my really old version of jq, both PADD and pi-hole are fully up-to-date:

$ ./padd.sh -v
PADD version is v4.1.0 (Latest: v4.1.0)

$ pihole -v
Core version is v6.3 (Latest: v6.3)
Web version is v6.4 (Latest: v6.4)
FTL version is v6.4.1 (Latest: v6.4.1)

$ jq --version
jq-1.5-1-a5b5cbe

How does this PR accomplish the above?:

Fixes the issue by converting json keys and values to strings using tostring before calling join().

The jq 1.6 documentation for join added this text when compared to the docs for v1.5:

Numbers and booleans in the input are converted to strings. Null values are treated as empty strings. Arrays and objects in the input are not supported.

I haven't done much with jq, so it took some trial and error to get my proposed fix. There might be a more elegant way to do it. Or, maybe you would prefer to require jq >= 1.6, which would be fine.

I've tested the one-liner in a terminal with jq 1.8 on a different machine, and as far as I can tell, my changed version continues to work correctly.

I did not (yet?) change the comment describing the jq invocation in GetPADDData, but maybe it should be.

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