fix(#2095): correct links broken by markdown conversion in #2017

[gmarav05]

While investigating the broken links introduced by the markdown conversion in #2017, I found and fixed the following issues.

Fixes #2095

1. Building page (content/en/building/_index.md)

   • [CHT Core Framework] was pointing to /building/local-setup.
   • Changed to /technical-overview/architecture/cht-core.

2. Architecture page (content/en/technical-overview/architecture/_index.md)

   • CHT Watchdog card was pointing to cht-conf.
   • Changed to cht-watchdog.

3. /core alias (content/en/technical-overview/architecture/cht-core.md)

   • /core was duplicated across three files (architecture/_index.md, concepts/_index.md, technical-overview/_index.md) causing it to incorrectly resolve to "Concepts and paradigms of the CHT" instead of the CHT Core Framework page.

   • Removed duplicate aliases from all three files and moved /core and /core/overview/ exclusively to cht-core.md, as confirmed by archive.org snapshot from May 2024.

[mrjones-plip]

wow! While relatively small changes, they have an outsized impact on make the docs site work as expected - thanks for these link fixes!

[gmarav05]

wow! While relatively small changes, they have an outsized impact on make the docs site work as expected - thanks for these link fixes!

Thank you for helping me out on this issue @mrjones-plip .