chore(cutover): retire v2 scaffolding (templates + plugin + config)

The v2 design is now the canonical design served at root URLs.
Delete base-v2.html, all v2_*.html templates, the v2_router Pelican
plugin, and the V2_*_SAVE_AS/URL + PLUGIN_PATHS/PLUGINS entries in
pelicanconf.py. /v2home/, /v2writings/, /v2theforge/, /v2/<slug>/
and /v2/pages/<slug>/ no longer exist.

Verification: rebuilt output/ has no output/v2* paths; all canonical
URLs (/, /writings/, /<slug>/, /pages/<slug>/) intact.

Author: Sohailm25

pelicanconf.py

@@ -45,22 +45,9 @@
 PAGE_SAVE_AS = "pages/{slug}/index.html"
 ARTICLE_URL = "{slug}/"
 ARTICLE_SAVE_AS = "{slug}/index.html"
-DIRECT_TEMPLATES = ("index", "archives", "v2_index", "v2_archives", "v2_theforge")
+DIRECT_TEMPLATES = ("index", "archives")
 ARCHIVES_SAVE_AS = "writings/index.html"
 
-# v2 parallel deployment — same article/page data, rendered through v2_*.html templates
-# at /v2home/, /v2writings/, /v2theforge/, plus per-article /v2/<slug>/ via the
-# v2_router plugin. Old site remains unchanged.
-V2_INDEX_SAVE_AS = "v2home/index.html"
-V2_INDEX_URL = "v2home/"
-V2_ARCHIVES_SAVE_AS = "v2writings/index.html"
-V2_ARCHIVES_URL = "v2writings/"
-V2_THEFORGE_SAVE_AS = "v2theforge/index.html"
-V2_THEFORGE_URL = "v2theforge/"
-
-PLUGIN_PATHS = ["plugins"]
-PLUGINS = ["v2_router"]
-
 TAG_SAVE_AS = ""
 CATEGORY_SAVE_AS = ""
 AUTHOR_SAVE_AS = ""