docs: Standardize all IndieAuth spec references to W3C URL

- Updated 42 references from indieauth.spec.indieweb.org to www.w3.org/TR/indieauth
- Ensures consistency across all documentation
- Points to the authoritative W3C specification
- No functional changes, documentation update only

Generated with Claude Code

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

docs/architecture/indieauth-client-diagnosis.md

@@ -134,6 +134,6 @@ After fixing:
 
 ## References
 
-- [IndieAuth Spec - Client Information Discovery](https://indieauth.spec.indieweb.org/#client-information-discovery)
+- [IndieAuth Spec - Client Information Discovery](https://www.w3.org/TR/indieauth/#client-information-discovery)
 - [Microformats h-app](http://microformats.org/wiki/h-app)
 - [IndieWeb Client ID](https://indieweb.org/client_id)

docs/architecture/indieauth-identity-page.md

@@ -149,7 +149,7 @@ See `/docs/examples/identity-page.html` for a complete, working example that can
 
 ## Standards References
 
-- [IndieAuth Specification](https://indieauth.spec.indieweb.org/)
+- [IndieAuth Specification](https://www.w3.org/TR/indieauth/)
 - [Microformats2 h-card](http://microformats.org/wiki/h-card)
 - [rel="me" specification](https://microformats.org/wiki/rel-me)
 - [IndieWeb Authentication](https://indieweb.org/authentication)

docs/architecture/overview.md

@@ -1123,7 +1123,7 @@ The architecture is successful if it enables:
 
 ### External Standards
 - [IndieWeb](https://indieweb.org/)
-- [IndieAuth Spec](https://indieauth.spec.indieweb.org/)
+- [IndieAuth Spec](https://www.w3.org/TR/indieauth/)
 - [Micropub Spec](https://micropub.spec.indieweb.org/)
 - [Microformats2](http://microformats.org/wiki/h-entry)
 - [RSS 2.0](https://www.rssboard.org/rss-specification)

docs/architecture/technology-stack.md

@@ -725,7 +725,7 @@ Return success
 **Token Format**: Bearer tokens
 **Validation**: Token introspection
 
-**Reference**: https://indieauth.spec.indieweb.org/
+**Reference**: https://www.w3.org/TR/indieauth/
 
 #### Micropub
 **Compliance**: Full Micropub spec support
@@ -1061,7 +1061,7 @@ This stack embodies the project philosophy: "Every line of code must justify its
 
 ### Standards and Specifications
 - IndieWeb: https://indieweb.org/
-- IndieAuth Spec: https://indieauth.spec.indieweb.org/
+- IndieAuth Spec: https://www.w3.org/TR/indieauth/
 - Micropub Spec: https://micropub.spec.indieweb.org/
 - Microformats2: http://microformats.org/wiki/h-entry
 - RSS 2.0: https://www.rssboard.org/rss-specification