Fix typos, casing, spacing and reference problems

[Mark90]

Tool-assisted review:

• Fixed several typos and misspellings (localhost, "first", "hierarchy", "redundancy", "manufacturers", a mistyped code sample, apostrophe misuse on plurals like "NRENs"/"L2VPNs"/"LSPs")
• Corrected "login into" → "log in to" and a garbled/comma-broken sentence about clicking through a workflow form
• Made NetBox and containerlab branding consistent throughout (was inconsistently cased)
• Fixed a wrong folder-tree diagram so it matches the real repo layout
• Filled a gap in the workshop overview that skipped mentioning the entire Workflows section
• Aligned a fragile branch reference (was pointing to a branch that doesn't actually exist) across five pages
• Added missing page titles to four workflow pages for consistency with their sibling pages
• Minor admonition/formatting fixes (stray hyphen, double space, mismatched capitalization)