docs: align README and docs with Shannon / Keygraph naming

Replace the README with the marketing-reviewed version and bring the
project onto one consistent naming scheme:

- "Shannon Lite" -> "Shannon" (the open-source CLI is just Shannon)
- "Shannon Pro" -> "Keygraph" (the commercial platform)
- Rename docs/shannon-pro.md -> docs/keygraph-platform.md and fix the
  internal link, matching the README's link target.
- Regenerate llms.txt and llms-full.txt from the updated README and docs.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/coverage-roadmap.md

@@ -1,8 +1,8 @@
 # Coverage and Roadmap
 
-Shannon Lite focuses on exploitable findings that can be validated against a running application.
+Shannon focuses on exploitable findings that can be validated against a running application.
 
-## Current Shannon Lite Coverage
+## Current Shannon Coverage
 
 - Broken Authentication
 - Broken Authorization
@@ -12,12 +12,12 @@ Shannon Lite focuses on exploitable findings that can be validated against a run
 
 ## Reporting Philosophy
 
-Shannon Lite follows a proof-by-exploitation model. Findings that cannot be demonstrated with a working proof of concept are not included in the final report.
+Shannon follows a proof-by-exploitation model. Findings that cannot be demonstrated with a working proof of concept are not included in the final report.
 
-This reduces speculative noise, but it also means Shannon Lite does not aim to report every possible security issue in a repository. In particular, many dependency, policy, configuration, and broad static-analysis findings are outside the core Shannon Lite workflow.
+This reduces speculative noise, but it also means Shannon does not aim to report every possible security issue in a repository. In particular, many dependency, policy, configuration, and broad static-analysis findings are outside the core Shannon workflow.
 
 ## Roadmap Direction
 
 Planned coverage areas should continue to live in the repository's canonical roadmap document if one exists. The README should link to that document rather than carrying detailed roadmap history inline.
 
-For organizations that need broader static and organizational coverage now, see [Shannon Pro](shannon-pro.md).
+For organizations that need broader static and organizational coverage now, see [Keygraph](keygraph-platform.md).