ISD-5226 update docs landing pages

[Thanhphan1147]

Checklist

• The charm style guide was applied
• The contributing guide was applied
• The changes are compliant with ISD054 - Managing Charm Complexity
• The documentation is updated
• A change artifact was added for user-relevant changes in docs/release-notes/artifacts. If this PR does not require a change artifact, the PR has been tagged with no-release-note.
• The PR is tagged with appropriate label (urgent, trivial, complex)
• The changelog is updated with user-relevant changes in the format of keep a changelog v1.1.0

[erinecon]

Thanks so much for implementing a structure and organization pattern for the how-to guides! With a bit more description, I think this landing page will be an excellent model for our other projects to follow :D

[erinecon]

Thanks so much!

[github-actions]

Test results for commit c0633f9

Test coverage for c0633f9

Name                                       Stmts   Miss Branch BrPart  Cover   Missing
--------------------------------------------------------------------------------------
lib/charms/haproxy/v0/ddos_protection.py     154     51     34      8    64%   157-174, 183-187, 288, 316-318, 323, 326-330, 342-344, 381, 387, 393, 396, 424, 495-498, 510-529
src/charm.py                                  21      0      0      0   100%
src/state.py                                  43      0      0      0   100%
--------------------------------------------------------------------------------------
TOTAL                                        218     51     34      8    73%

Static code analysis report

Run started:2026-03-14 01:49:32.801216+00:00

Test results:
  No issues identified.

Code scanned:
  Total lines of code: 333
  Total lines skipped (#nosec): 0
  Total potential issues skipped due to specifically being disabled (e.g., #nosec BXXX): 0

Run metrics:
  Total issues (by severity):
  	Undefined: 0
  	Low: 0
  	Medium: 0
  	High: 0
  Total issues (by confidence):
  	Undefined: 0
  	Low: 0
  	Medium: 0
  	High: 0
Files skipped (0):

[github-actions]

Test results for commit c0633f9

Test coverage for c0633f9

Name                                         Stmts   Miss Branch BrPart  Cover   Missing
----------------------------------------------------------------------------------------
lib/charms/haproxy/v0/ddos_protection.py       154     42     34      3    72%   157-174, 183-187, 265, 284, 415-418, 422-424, 459-478, 514-529
lib/charms/haproxy/v0/spoe_auth.py             158     55     32      2    59%   203, 304-306, 315, 354-381, 392-402, 441-442, 459-472, 484-501, 522-525, 529-531
lib/charms/haproxy/v1/haproxy_route_tcp.py     385    153     78      8    56%   209, 212, 281, 290-293, 297-300, 318-321, 336, 342-347, 447, 452, 829-832, 836, 863-874, 897-900, 904-906, 926-928, 1042-1083, 1087-1093, 1097, 1166-1195, 1266-1305, 1335-1337, 1362-1364, 1386-1390, 1409-1411, 1429-1431, 1438-1444, 1452-1454, 1462-1463, 1474-1481, 1494-1505, 1513-1534, 1546-1547, 1558-1559, 1570-1573, 1584-1585, 1614-1623, 1639-1642, 1658-1669, 1685-1688, 1706-1717, 1728-1729, 1737-1738, 1746-1747, 1758-1761
lib/charms/haproxy/v2/haproxy_route.py         385     53     98     26    82%   181, 257, 266-269, 294-297, 318-323, 673-674, 860->exit, 867, 893-904, 927-930, 934-936, 955-957, 1129-1135, 1139, 1336->1338, 1340->1342, 1342->1344, 1344->1346, 1346->1348, 1348->1351, 1386, 1394, 1399, 1402, 1427, 1455, 1459, 1463, 1486, 1506, 1515-1516, 1518->exit, 1554-1556, 1576, 1590, 1595-1597
src/charm.py                                   286     69     78     11    71%   100, 228, 236-252, 257, 262, 279, 290, 296-297, 331-351, 455-463, 491-504, 517-522, 531, 544-545, 552, 562, 572, 578-584, 600, 650-653, 659->658, 672-675
src/haproxy.py                                 127     31      6      2    75%   110-116, 136-158, 268-269, 272, 280-286, 314, 344-355, 367-369, 379-380
src/http_interface.py                           73     25      4      0    62%   74, 83, 92, 106-108, 126, 138, 150, 162, 170-175, 187, 194, 202, 217-227
src/state/charm_state.py                        77     15     14      4    79%   93-95, 100-101, 104, 145-150, 159, 208-210, 222-223
src/state/ddos_protection.py                    39      0      2      0   100%
src/state/exception.py                           1      0      0      0   100%
src/state/ha.py                                 30      1      2      1    94%   50
src/state/haproxy_route.py                     197     14     60      5    90%   132, 161-170, 194, 227, 297, 346-348, 365
src/state/haproxy_route_tcp.py                 120     17     42      1    80%   92-94, 109->112, 147-160
src/state/ingress.py                            38      0      4      0   100%
src/state/ingress_per_unit.py                   32      0      4      0   100%
src/state/spoe_auth.py                          26      2      2      0    93%   63-64
src/state/tls.py                                39      7     12      4    78%   74, 77-78, 127-135, 141-142
src/state/validation.py                         46     23      8      1    44%   66-67, 71-98
src/tls_relation.py                             61      3     14      3    92%   86->85, 118-128, 140->142
----------------------------------------------------------------------------------------
TOTAL                                         2274    510    494     71    74%

Static code analysis report

Working... ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 100% 0:00:00
Run started:2026-03-14 01:07:58.460136+00:00

Test results:
  No issues identified.

Code scanned:
  Total lines of code: 10203
  Total lines skipped (#nosec): 13
  Total potential issues skipped due to specifically being disabled (e.g., #nosec BXXX): 10

Run metrics:
  Total issues (by severity):
  	Undefined: 0
  	Low: 0
  	Medium: 0
  	High: 0
  Total issues (by confidence):
  	Undefined: 0
  	Low: 0
  	Medium: 0
  	High: 0
Files skipped (0):

[github-actions]

Test results for commit c0633f9

Test coverage for c0633f9

Name                               Stmts   Miss Branch BrPart  Cover   Missing
------------------------------------------------------------------------------
src/charm.py                          45      9      2      0    77%   65-91, 96-98
src/haproxy_spoe_auth_service.py      44     16      2      0    61%   56-64, 76-82, 93-117
src/state.py                          55     15      6      1    67%   64-66, 79, 125-146
------------------------------------------------------------------------------
TOTAL                                144     40     10      1    68%

Static code analysis report

Run started:2026-03-14 01:21:06.466048

Test results:
  No issues identified.

Code scanned:
  Total lines of code: 409
  Total lines skipped (#nosec): 1
  Total potential issues skipped due to specifically being disabled (e.g., #nosec BXXX): 1

Run metrics:
  Total issues (by severity):
  	Undefined: 0
  	Low: 0
  	Medium: 0
  	High: 0
  Total issues (by confidence):
  	Undefined: 0
  	Low: 0
  	Medium: 0
  	High: 0
Files skipped (0):